Tech: temporary power supplies for festivals

Subject: RE: Tech: temporary power supplies for festivals
From: Richard Bridge
Date: 31 May 06 - 08:43 PM

That bunch of guys did not use PA or hence mains electricity.

Subject: RE: Tech: temporary power supplies for festivals
From: folk1e
Date: 31 May 06 - 07:35 PM

HSE!

Subject: RE: Tech: temporary power supplies for festivals
From: The Fooles Troupe
Date: 29 May 06 - 08:36 AM

Gawd, whatever happened to a bunch of guys knowing a friendly farmer, and settling down in his field for the weekend with a stack of booze and instruments?

:-)

Subject: RE: Tech: temporary power supplies for festivals
From: Folkiedave
Date: 28 May 06 - 12:54 PM

One answer to your question is "PEL" which implies health and safety.

No such thing since the Licensing Act 2003. Where is the venue? Does it have premises licence? Does it normally provide regulated entertainment an is covered by the Act to do so? Things like a theatre, civic or viallge ghall etc.

Otherwise (and if you are needing a generator this seems likely) you need a temporary event notice. (TEN) Limits you to 499 people plus a host of other things. See the DCMS website for details.

http://www.culture.gov.uk/alcohol_and_entertainment/licensing_act_2003/permitted_temporary_activities.htm

Most important thing - ten working days notice. As far as I can see from your webiste there are some activities that will need a license.

Feel free to contact me via a PM for any further advice.

Subject: RE: Tech: temporary power supplies for festivals
From: folk1e
Date: 28 May 06 - 12:49 PM

The rule of thumb here in the U.K. is to think of a (large) number and times it by the number of days until your birthday! Typicaly you would be loking at four digits in £ stirling!
The work woul entail digging a trench from the nearest suply feed, running a cable (20mm split concentric) jointing one end and terminating the other in a custom built (by you) brick shed via a 100 amp cutout and meter! Don't even ask "what if it is overhead line fed"!Then you need to arrange for a supplier to take you on. Don't forget you are not a source of rvenue to these guys! Unless you are going to be visiting the same site anualy this is NOT AN OPTION! Sorry I forgot to mention that you still need to have your instilation checked (anualy) to ensure it complies to the I.E.E.Regulations, for which you need to be NJIC/NIC approved (a typical house check is about £100). KISS (Keep It Simple Stupid!) Use a generator with your sound guy's own kit plugged in! It should be coverd by a Portable Appliance Test (sticker on the plug)! If he/she is a professional they will have their own insurance as well!
Sorry to winge on but this stuff is the only thing keeping you out of Jail if somebody gets hurt..... not that they will

Subject: RE: Tech: temporary power supplies for festivals
From: JohnInKansas
Date: 28 May 06 - 09:33 AM

There was some discussion over the lack of plugs in the campground at our big festival (US) 3 or 4 years ago, and one of the fellows who claimed to be a know-everything-licensed-master-electrician was claiming it would cost about $100 - $150 (US) in setup and takedown for a temporary "construction pole" of the kind they put up while a new house is being built, before the lines are run in. That might not look unreasonable if you were going to run saws and sanders off it for a couple of months, but it's a bit steep for a half-day festival, unless you've got a dozen or so users sharing to kick in on the fee.

With the distance wanted here, it's likely that a couple of intermediate line support poles would be wanted, which would probably cost a bit on a per-pole basis in addition to the one with the plugs on it.

Note that as far as I know, nobody called the guys that would have to install it to check out this "expert advice;" and different markets would have different costs.

John

Subject: RE: Tech: temporary power supplies for festivals
From: The Fooles Troupe
Date: 28 May 06 - 07:12 AM

Well folk1e - here in Australia, for about the cost of 2 and a bit years of generator power, Maleny was able to get full 3 phase standard reticulation permanently installed - poles and leadin from highway and all.

Subject: RE: Tech: temporary power supplies for festivals
From: folk1e
Date: 27 May 06 - 08:33 PM

There are generator sets that will run that load with ease and do it quietly too! There are a raft of regulations you MUST comply with (unles you are "glastonbry"! Ask your spark if he is wiling and able to do this sort of instilation (not all can do it) There are problems with all types of power suply!
Forget the Power companies (YOU CAN'T AFORD THEM)
"Part P" is only for Domestic Instilations
Deni C if you ned any more information from an old(ish) sparkie PM me!

Subject: RE: Tech: temporary power supplies for festivals
From: GUEST,Deni-c
Date: 27 May 06 - 06:08 PM

...Now if someone keen wants to come up and demonstrate solar power, maybe we'll go solar next year...

I went to ican where they had solar powered showers etc....
D

Subject: RE: Tech: temporary power supplies for festivals
From: JohnInKansas
Date: 27 May 06 - 05:28 PM

Solar power should be quite usable in the UK, although you may need a few more panels than in New Mexico for a given output. Currently available panels can work from diffused light, although the output may be lower than with direct-incident sunlight.

The real bottle-necks to using solar in lots of situations is that you need storage batteries and an inverter to run most kinds of "appliances" from it. At anything beyond a radio/TV or a few lighting devices the "associated equipment" outstrips the cost of the panels (and is far less portable).

John

Subject: RE: Tech: temporary power supplies for festivals
From: Richard Bridge
Date: 27 May 06 - 01:46 PM

Solar power - in the UK? Are you having a giraffe?

Subject: RE: Tech: temporary power supplies for festivals
From: EBarnacle
Date: 27 May 06 - 01:15 PM

You just said the masgic words. 11-4 PM. You can probably go solar for less than the cost of all the other fixes. Clearwater's Revival does this every year as a demonstration project for at least one stage. We have never had a problem with short voltage.

Subject: RE: Tech: temporary power supplies for festivals
From: GUEST,Deni-C
Date: 27 May 06 - 12:37 PM

Here is info Richard

Thanks again to those who commented.

june 10-11. Plymouth city centre (UK) and Freedom park. 11- 4 pm.

What we are trying for the first time is marquees with music in Freedom Park, Greenbank, Plymouth on the Sunday. We hope it will build in future!!!


WE do have risk assessments and all sorts, as well as a trained electrician. i will bear in mind what you have said and tell our tech too.

Cheers
Deni

Subject: RE: Tech: temporary power supplies for festivals
From: Richard Bridge
Date: 25 May 06 - 06:15 PM

You will probably have to PAT test EVERY SINGLE LEAD (including mic and guitar leads) you plan to use, and every item of equipment to be connected. The usual cost is £20 per item (!!!) That alone makes it cheaper to get a proper hire company to do the PA.

But 600 watts is not a lot for a marquee in the open air even for a largely acoustic thing. The most important thing is to remember not to turn up too much if you don't need to. I have seen an acoustic player with a mandolin (a piercing instrument at best) unable to compete with the noise from drunken Henry and Harriet in a pub despite a 1k PA rig. But that ought not to happen at a Folk fest.

What date is this event - it sounds like a nice amateur vibe to it (and I am an old fart)?

What is the fringe like, the sinagrounds and stuff?

Subject: RE: Tech: temporary power supplies for festivals
From: GUEST,Auldtimer
Date: 25 May 06 - 01:23 PM

There will be umteen regulations regarding tempory power supplies, so ensure that ONLY profesional electricians are involved in the installation testing and certificating of these supplies, this is NOT A JOB FOR ANY WELL MEANING HANDY MAN. RCD protection and earth electrodes will be required and appliance testing of all equipment concidered. Contact your electricin in plenty of time, at least a week in advance. As for a 100M to 200M cable run? A fairly hefty and expensive cable will be required, 10mm,16mm maybe 25mm, and conderation about any roads and access points so as cars, vans or even pedestrians won't cause any dammage or be injured themselves. I asume you have insurance cover for the event? They will wash their hands over any claims if if the instalation is not 100% pukka. I have worked in the electrical industiy for more than 40 years this and is not a two hour job more like two days maybe three and it will have to be cleared up after the festival.

Subject: RE: Tech: temporary power supplies for festivals
From: GUEST,Deni-C
Date: 25 May 06 - 10:41 AM

hi Mr Red, long time no hear!! It's Plymouth Folk Festival. you asked where it is so you can avoid it...
it's only a small local festival run by volunteers not a big commercial event, but is there a thread here where I can publicise it or do I have to start a new thread?

WE have an acoustic marquee and a main marquee with PA. We are not planning to have the volume up high at this one, just sos it can be heard and the singers and quieter instruments don't have to strain. The only reason it is a 600w pA is because we are borrowing it from a musician and that's the only size he's got.
:-}
Regards

Deni

Subject: RE: Tech: temporary power supplies for festivals
From: GUEST,.gargoyle
Date: 22 May 06 - 08:10 PM

From my experiences. The local power utility - was generally more than happy to help you have safe, healthy, voltage and will run temporary lines for even a weekend event.

Sincerely,
Gargoyle

Subject: RE: Tech: temporary power supplies for festivals
From: Mr Red
Date: 22 May 06 - 05:41 PM

Would this be Folk - or entertainment?

tell me the festival & I will avoid it.

There are times when I am ashamed of my profession. The invention of the amplifier isn't it but cheap mega watt ones is. It does detract from the pleasure I get from designing useful items.

One answer to your question is "PEL" which implies health and safety. For all it's concern to screw money out of organisers the law does not address hearing loss.

Subject: RE: Tech: temporary power supplies for festivals
From: skipy
Date: 22 May 06 - 12:41 PM

Get an electrian, you can do the work yourself as stated, then pay to have it checked, which will get you a cert. Your insurance is no more than a piece of paper if you or a mate just does it.
If you are a member of AFO (see above) you may be able to borrow / hire from another festival, both genny & leads, the kit may well be pat tested & carry certs. Otherwise try the hire shops, not cheap but safe & certificated, perhaps a reduction for sponsorship?
There is no safe way around this one.
Think about prison food & the showers!
Skipy.

Subject: RE: Tech: temporary power supplies for festivals
From: JohnInKansas
Date: 22 May 06 - 12:12 PM

While I, like Foolestroupe, have the typical ol'-fart distaste for amplified noise, he's a lot younger than I am, so he'll get even worse eventually.

The problem of "portable" or "remote" electrical power is a very real one for those who camp, including especially those of us who go to extended festivals. At the WVA festival, I usually plan on arrival approximately 3 weeks prior to the start of the fest to get in line for the line to get in line for the lineup that determines who gets first run at the limited number of outlets available.

Being "power self-sufficient" would be really nice, so if someone comes up with something that really works, I'm sure a lot of us would like to hear about it.

There are no portable generators on the market, that I've been able to find, that are not too noisy to be acceptable in a campground, although for limited use you might get by with running one of the quieter ones periodically, and briefly, to recharge storage batteries.

On the US market, Coleman makes a fairly quiet "camp generator" and a couple of other makers use a larger but reasonably quiet Honda engine for small configurations. Not really quiet enough for a music campground, but perhaps good enough for a "sales venue" or where there's a fair amount of crowd noise. The really small ones would likely have marginal output capacity for the use described, and they are not particularly fuel-efficient and require frequent refueling. (If you have more than a once-in-a-lifetime need, and a place for storage, buying a generator may be ultimately cheaper than renting.)

Even in (sometimes) sunny Kansas, solar recharging could take care of part of the recharge requirement for minimal use such as camp lights and perhaps even a bit of TV, but it would take larger (and more expensive) than commonly available "mobile" solar panels to keep up with more than "incidental" use. (Solar panels can provide some power in overcast/foggy conditions, but I won't comment on their relative usefulness in the UK.) With solar, even keeping sufficent charge to assure that the furnace will work if it turns cold is marginal. And with solar, as with small generators, you need lots of batteries.

Installed RV generator systems in a reasonably large RV can be made quiet enough to produce only minimal objections from fellow campers, but an installation is expensive. Typical generator sizes run from about 3 to 5 KW, quite similar to the most popular sizes in "portables." That's about enough to run one 10-15 KBtu air conditioner, OR everything else one's likely to have,but not both at the same time. While you can run the generator whenever you want to use the "big appliances" it's not too fuel efficient to have them running all the time, so the usual setup is to charge a bank of 2 to 6 batteries, and use a solid state inverter to produce AC for things that need it. A good inverter can also provide "clean enough" AC for electronics that might barf at direct generator power. A significant part of the rather stunning installation cost for the self-contained units is for the ¹5 KW (or larger) inverter you need for this system - starting at around $700 US for a minimal one; and of course the batteries aren't free, are really heavy, and require regular maintenance.

¹ With a 3KW generator, you need at least a 5KW inverter, because you can take power out of the batteries much faster than you can put it back in.

For a one-day setup, using less than 1KW for 8 hours or less, one might be able to get a smaller inverter and simply run off batteries for a day. Truck stops sell "near 1KW" inverters for about $150 - $250 for truckers who want a TV and Refrigerator in the sleeper, although I haven't shopped around to see if better deals are available. Whether a half-dozen batteries (about what's in a golf cart) might suffice to keep you running all day, with overnight recharging from an outlet you could take the batteries and charger to, would depend on battery sizes and quality. I've made some calculations on this, on the assumption I could take the batteries and a small generator outside the campground for a few hours of recharging. A practical setup for my situation isn't easy to come up with since the load is extremely variable and not really predictable; but if one had a specific appliance to run for a known, consistent, and predictable time between charging, it might be feasible.

When I find the perfect low-cost fuel-efficient no-noise solution, I'll be sure to pass it along; but for now I'm still looking - and have been for at least 5 years or so. I've found some "really exciting concepts," but nothing ready for market as yet.

John

Subject: RE: Tech: temporary power supplies for festivals
From: The Fooles Troupe
Date: 22 May 06 - 07:52 AM

Perhaps teh most elagant answer is:

"How do other people get around the question of power for a 600w PA in a marquee????"

Dump the PA idea... or are you confused between a rock concert and folk musicians?

:0

Subject: RE: Tech: temporary power supplies for festivals
From: GUEST,deni C
Date: 22 May 06 - 07:08 AM

we're lucky in that we have a trained electrician on our committee. He will have to oversee the safety aspects and of course we need a risk assessment for our local council. Thanks very much for all the advice. fantastic. I've read through and go on to the next bit armed with a lot more idea than before.

Thanks again everyone.

Deni-c

Subject: RE: Tech: temporary power supplies for festivals
From: GUEST,Jon
Date: 22 May 06 - 03:40 AM

I am reasonably sure that something in recent UK planning law has changed and it is now illegal not to use a qualified electrician even to install your own mains wiring for garden lighting

It's the so called "part P". As far as I understand it, it doesn't prevent a "DIYer" from carrying out the work you mention but to go about things that way, Building control needs to be notified before the work is started and the work has to be inspected after the work is completed. I'd imagine by the time one is done and paid the fees, one might as well have just paid a qualified electrician to do the job.

Subject: RE: Tech: temporary power supplies for festivals
From: JohnInKansas
Date: 22 May 06 - 02:19 AM

The sample calculation for voltage drop that I gave above was of course for 200 feet, which is about as long a run as can be made with a "temporary" cord, where that's permissible, not for the 200 yard distance requested.

In the US, it's fairly easy to get what's called a "construction pole" installed by the local electrical provider, and that could be the preferred solution here. Depending on how many support poles have to be placed to reach the nearest HV line, it may not cost as much as one might think, since all the parts and pieces can be re-used by the electric company; but if several support poles are needed to get to the location it can run into a significant expense.

Even ignoring the cost factor, the generators that are cheaply rentable usually are noisy enough to be a distraction in a crowd situation. If you really need a 700W PA, that may imply a noisy enough environ to drown out the generator, but in a campground they often get complaints.

Very small "camp generators" can be purchased for around $150 (US) but would provide marginal power for your use (<1KW). The littlest ones typically run only for an hour or two before refueling is required; and for safe refueling they need to be shut down long enough to cool a bit each time.

"Portable" generators of useful size (~3 KW) can be bought here for around $350-$400 (US) but still have the problems of noise and short runtime (3 to 6 hours?) between refueling. They run around 150 - 250 pounds, and are bulky but transportable. Of course you need someplace to store them between uses.

With a small generator, the problem of storing enough fuel for a day's run nearby may be as likely to violate building/use codes as the fact of having an electrical setup. Here the local Fire Department would be the one to give you advice on the fuel storage requirements. This can also be a problem if you rent a generator, so if that's the last-best-option you should try to get an accurate estimation of fuel consumption and run-time between refuelings.

A very few places (that I've noticed without looking) offer the portable generators in the 3 - 5 KW range for rental, and the rental cost for a few days ran almost to purchase price the last time I asked, several years ago. The more common offering from rental outlets here would be a 10-15KW trailer unit, or perhaps a 15-30KW "welding trailer." These are in the multi-K$ range to buy, and are "industrial strength" so the purchase cost can be recovered over longer times/more uses by the rental places, so they're more reasonable in proportion to value - sometimes.

If you wanted to go first-class, RVs can have an "installed generator." Rent or borrow? These are essentially the same machines as the $350 3-5KW units mentioned above, but installed in a sound containment box and operating off the RV fuel or propane tanks. Virtually noiseless in a good installation, and no refueling or fuel storage problem. They're less common than might be expected, given their almost "unnoticebly quiet" operation when properly installed and the flexibility for picking camp sites that they provide; but the installation costs run typically to about $2,000+, so they tend to appear only in the "monster class" vehicles. (>50'?) Persuade a friend to park his/her RV nearby? Of course it would need to be a very dear, sympathetic, and wealthy(?) friend.

John

Subject: RE: Tech: temporary power supplies for festivals
From: Bonecruncher
Date: 21 May 06 - 09:20 PM

Guest Deni C
Richard Bridge (above) is correct.
Any PERMANANT extension to ANY electrical system must be certificated by a qualified electrician who ALSO holds the necessary certification qualifications (not all of them do - it means courses, tests, and another bit of paper). This includes do-it-yourself installation.
If it is only a plug-in extension you will be limited by a maximum 13-Amp fuse in the plug.
As has been advised, you would be advised to talk to the Association of Festival Organisers and your Insurers.
If you do use a plug-in cable you should be able to obtain sufficient length in one reel from an electrical wholesaler. Far cheaper (and safer) than several short lengths plugged together. The wholesaler I use is TLC, who do a delivery service if you cannot get to them. Look in your Yellow Pages under "Electrical Wholesalers".
Colyn.

Subject: RE: Tech: temporary power supplies for festivals
From: The Fooles Troupe
Date: 21 May 06 - 09:09 PM

Incidentally, in Australia, we rate (240V) cords by 'AMP rating' (not wire gauges, but the rules are there as to which gauges of wire to use for what ratings, both fixed and cords) 5, 7.5, 10 & 15 amp ratings. This is how things are advertised and marked for sale - just the 'rating' figure. All except the last come with '10A' rated (except for some lower rated appliances) plugs and sockets, the 15A one has a larger earth pin, so you can't plug it into 'normal' 10A rated sockets - it IS possible to plug a 10A plug into a 15A socket. It is possible to obtain ext cords with 15A cable and 10A plugs (marked as such) - intended as 'long' 'temporary' cords for caravans, building sites, etc. Fixed wiring for 'domestic' use is normally rated at 20A & 40A - lighting runs may have lighter gauges, eg 10A.

Note that now, all 'normal' (10A rated) appliance and extension plugs sold in Australia must have a narrowing of the part of the pins closest to the plug body so that some insulation is present if the plug is partly 'pulled' - this MAY cause some loading problems due to the lesser amount of metal in the plug pins, especially for long cords.

I once saw a hired cord used in theatre lighting - a Loooong one which had about 20 feet wrapped around a 2 inch diameter water pipe (used to suspend theatre lights from) which had melted, and finally blown the fuse! The hiring guy kept it to demonstrate at regular 'lighting seminars' just what idiots will do, and what not to do. And yes, I did met the clown who had done it, and he was a natural disaster walking around waiting to happen - a 'know everything ignoramus' - and he 'happened' to me several times, dammit...

When running cords thru areas with traffic (including foot) they should be suspended well clear of the ground - if buried (normally for 'permanent' installations), there are minimum depths and recommended coverings, such as broken rubble, etc below the top layer of dirt. Incidentally, the AGMF in Toowoomba was ignoring all these safety regs when I stumbled over the cords the other year - all attempts to get the authorities to enforce the laws (including the permitted noise levels!) have not worked - why would 'God Botherers' need to worry about that sort of thing? Render unto Caesar, oh... :)

Maleny Festival on its new grounds futzed around with generators and festoons of extension cables and double adaptors the first year, then bit the bullet and had the professionals run real mains power poles (and proper feed transformers, etc) around the place for the next year... this solved the endless power juggling, brownouts and fuse blowings as every stall holder constantly plugged and unplugged things!

Oh, and for real high power users, 3 phase feed is recommended, especially by the power companies!

By the way - get professional electricians to have a look at whay you are trying to do - it's cheaperin teh long run than the inevitable life insurance claims...

Subject: RE: Tech: temporary power supplies for festivals
From: Barry Finn
Date: 21 May 06 - 08:18 PM

Another though. I don't know how it is in the UK but in the US you'd most likely need an electrical permit along with some kind of OK from he local Fire Marshall.
Again good luck & let us know what you end up with
Barry

Subject: RE: Tech: temporary power supplies for festivals
From: Barry Finn
Date: 21 May 06 - 08:15 PM

100-200 yds is not an "extension cord", it's a "power line", talk to an ELECTRICIAN. On construction site, if I ran cords 600' I'd have to dedicate it for one tool, maybe a screw gun. You did say YARDS, right. If you run a generator, take care if you try to insulate for sound, you don't want to cut the generator's ventalation needs & burn it out or set it on fire, talk to an ELECTRICIAN. What exactly are you looking to power up? Speakers, amps, mixing boards, lights, RV's, instruments, hot dog stands & popcorn kiosks, tanning booths. Depending on what it's for will tell you the size of power supply, talk to an ELECTRICIAN. In rural areas when we'd run generators & compressors the sounds can REALLY travel. Is this for personnel use, commerical use, industrial use, talk to an ELECTRICIAN?
Good luck
Barry

Subject: RE: Tech: temporary power supplies for festivals
From: Richard Bridge
Date: 21 May 06 - 08:14 PM

With sufficient warning, an electrical contractor or even the local electricity board should be able to provide a decent and legal 30 amp supply this far from the nearest domestic fuse box. Look at the size of cable going into your typical domestic unit. That's what you will need, and you will need a secure and waterproof shelter for the fusebox that terminates the supply at the usage end. The cost is not likely to be nominal!

Assume you will be using 2Kva not 1Kva. That is more like 10 amps. As pointed out above, this does not include lighting. If you plan to cut corners and do it yourself, you should not use anything less than 30 amp exterior grade armoured cable. You may be able to get a price for a 100 metre drum at a builders' merchant's. You will need to bury it or have it far enough off the ground that neither people nor vehicles can touch it by at least 6 feet.

I am reasonably sure that something in recent UK planning law has changed and it is now illegal not to use a qualified electrician even to install your own mains wiring for garden lighting - so if you are planning to hold a public event, you almost certainly must by law only use a qualified electrician.

If you run something like this some idiot will fiddle with it so do make it as bulletproof as you can.

Subject: RE: Tech: temporary power supplies for festivals
From: s&r
Date: 21 May 06 - 06:58 PM

There don't seem to be any extension cables available longer than 50 metres. There are obvious problems with trailing cables. If on the ground they would need a good level of mechanical protection if in a walkway. RCDs would be a must. Get a qualified electrician.

Generators bring some problems; the mains output is usually 'dirty' with small industrial generators and not all PA equipment can cope, so you may have to supply extra filtering. Our last experience caused the level indicators on the mixer to indicate max all the time. Noise from the generator can be a problem.

Lighting uses a lot of power - is the event in the daylight?

Just some thoughts

Stu

Subject: RE: Tech: temporary power supplies for festivals
From: JohnInKansas
Date: 21 May 06 - 06:47 PM

At our major local (US) festival (WVA at Winfield KS) lots of people plug their campers in through 100' "extension cords" with relatively few problems. For a 20 Ampere service, the "breaker" size at most of the places we can plug in, and for "light loads" you would need a minimum of AWG12 (B&S#12) 3-wire cord at 50 feet, and might get by with that at up to 100 feet if you're not running an air conditioner or other high-demand device. With 100 feet of AWG12 cord, a microwave is "iffy."

For a "US standard RV" 30 Ampere connection, you should have a minimum AWG10 cord and many RVs use #8; and the recommendation is that you should not exceed the 30 to 50 foot cord length usually supplied with the RV, although people at this festival commonly run their air conditioners on 100 to 200 foot AWG10 "drops."

The AWG10 is the heaviest "portable" cord commonly available in my part of the US, and a 100 foot "extension cord" can be had for about $90 (US) or a little less with some shopping. It's commonly used by construction workers, so should be available at lumber or building materials outlets. It should be noted that it's about 35 or 40 pounds of extension cord, and doesn't tuck into a corner of the trunk (boot) easily.

With UK 220 Volt mains to plug into, you should get by with a more compact cord, but voltage drop may still be a problem with common "household" or "yardwork" cords if you're operating at more than nominal load and beyond 50 feet or so.

Packaging on new extension cords should show an ampere rating for the length of cord in the package. If you can find a cord long enough for your use, and use shorter cords all of the same wire gage as the full length one, you should be fairly safe, although each connection adds a small bit of additional drop.

With UK 220 volt circuits, your 600W PA may have an actual peak input power requirement of about 1,000 Watts, so it should run at not more than about 4.5 Amps (peak). You can probably check the nameplate for a "Peak Amps" required.

Because of the lower voltage used in the US, the lightest wire size I have info handy for is a B&S12 (or AWG12) which should have a resistance (at 50C) of about 1.775 Ohms per 1,000 feet, so your 200 foot extension cord would have a nominal resistance of about 0.355 ohms per wire. At 4.5 amps, this would give a "drop" of 0.355*4.5 = 1.6 volts. Since both the "in" and "out" wires carry the same current, you'll lose about 3.2 volts between the input and output ends of the cord. You'll need to check the ratings on voltage tolerance for your amp to see if that's acceptable.

Factors that require special consideration:

1. If the cord is where any foot or vehicle traffic may cross it, you likely will want a more "robust" cord than is required strictly from the electrical capacity needed. You may also need a way of "tying the cord down" to prevent tripping, and to minimize wear on the cord if it gets trampled or kicked around. On a hard floor, you can perhaps "duct tape it down" if the facility permits it.

2. Although the 4.5 Amps x 0.71 Ohms reflects a dissipation of only a small bit of power in the cord itself, it can be enough to raise the cord temperature significantly, and "local resistances" in plugs or kinks can easily create hot spots. The resistance of the cord wires goes up rapidly with increasing temperature, which increases the rate of heating, which can lead to additional voltage drop due to the heating or to failure of the cord, especially if a bit of extra length is wound up in a pile so that heat is not easily dissipated. And note that "taping it down" holds the heat in too.

3. Any connector that's exposed can be rapidly burned out if any moisture gets in. Outdoors, it's often the morning dew. Indoors, it can be a klutz with a cup of cofee. Our campers sometimes "duct tape" the connectors, but a better procedure is to wrap the connectors with a baggie, and duct tape the baggie, when needed.

It's far more likely that the venue operators will impose limitations on what you can do than that there are regulations specifically prohibiting anything that will apply. If regulations do apply, the venue operators should know about them. (Or are you the venue operator?)

John

Subject: RE: Tech: temporary power supplies for festivals
From: Malcolm Douglas
Date: 21 May 06 - 06:35 PM

It's likely to be covered by health and safety legislation. You should consult the relevant local authority, but also contact The Association of Festival Organisers.

Since there are likely to be issues involving your public liability insurance, you must get proper advice. Most festivals would probably use a generator to provide power that far from a mains supply.

Subject: RE: Tech: temporary power supplies for festivals
From: open mike
Date: 21 May 06 - 06:29 PM

the kate wolf festival has one stage that is powered by solar...
this would require storage batteries..and a hope that you
would have a sunny day...you can look up kate wolf memorial music fest
and see about the Arlo Hagler stage i think it is called.

Cloud Moss, the organizer could put you in touch with the
people who work on this.

also see real goods solar and Solar Living Institute for more info.

Subject: RE: Tech: temporary power supplies for festivals
From: The Fooles Troupe
Date: 21 May 06 - 06:25 PM

Go Unplugged!

Subject: RE: Tech: temporary power supplies for festivals
From: Bert
Date: 21 May 06 - 06:15 PM

Power drop on 240 volts is not too bad if you use a thick enough cable.

A 600 watt supply is also not too great for a generator. A 1000 watt generator is quite small and if you're doing a lot of that thing would be cheaper to purchase than to rent, mine cost about $800. Of course over there it might be a bit more nowadays. (how much does 600 feet of cable cost?) It should use about a gallon of gas per hour.

A few sheets of urethane foam insulation, strategically placed should keep the sound down to a reasonable level.

And don't forget to check with your audience and local farmers (I'm assuming that your location is rural). Someone might just have one that they would lend you.

Subject: RE: Tech: temporary power supplies for festivals
From: s&r
Date: 21 May 06 - 05:55 PM

What sort of lighting will you have?

Stu

Subject: RE: Tech: temporary power supplies for festivals
From: GUEST,Jon
Date: 21 May 06 - 04:54 PM

It's a voltage drop. Basically, the required thickness of a type of cable is governed by the length of run and the current it has to carry.

Subject: RE: Tech: temporary power supplies for festivals
From: GUEST
Date: 21 May 06 - 04:50 PM

Sorry.. I mean UK. And what is that about amperage decreasing with the length of the lead? Even more complex than I'd thought!!!

Cheers
deni

Subject: RE: Tech: temporary power supplies for festivals
From: DMcG
Date: 21 May 06 - 04:43 PM

We've been looking for any legislation that prevents us from trailing a lead...

US?
UK?
Australian?

Subject: RE: Tech: temporary power supplies for festivals
From: Sorcha
Date: 21 May 06 - 04:42 PM

Well, all I know is that the longer the line, the less power at the end of it. Think it's the amperage that is decreased????

Subject: Tech: temporary power supplies for festivals
From: GUEST,Deni C
Date: 21 May 06 - 04:29 PM

hello there

Had a quick look for advice for festival organisers, but nothing came up. We've been looking for any legislation that prevents us from trailing a lead, (with necessary safety precautions) about 100 -200 yards from a power point. Generators are noisy, expensive and difficult to transport and have a 400 pound deposit. How do other people get around the question of power for a 600w PA in a marquee????

Cheers
Deni C