Mains power requirements for a gig?

allen

We have been asked to do a bit of playing at a friend's party next weekend and he has asked me about power requirements.

We will probably be playing on the patio if the weather is good.

My calculations/estimates (input power) are:
2 x guitar amps at around 200w each
1 x bass amp at around 400w (?)
3 x pa speakers (2 x stand mounted and 1 monitor) for singer 850w
little mixer (negligible?)
a few effects pedals

My sums say a total of 1650w

A 13 amp socket at 240v is theoretically (13 x 240) 3120 watts. However, I realise that a socket is not normally expected to do that so even if you are conservative and say 10amps, that's still 2400 watts available from one socket.

Other factors:
We are not a loud metal band, we are doing 80s/90s covers
It's outdoors so might need to turn the volume up

Anyone got any thoughts or advice?

ICBM

One 13A socket is plenty for that - those figures are peak draw not average too.

The best way to do it is with one heavy duty proper 13A-rated 4-way extension, and then four more plugged into that, which can be lighter rated, giving a total of 16 outlets. Don’t daisy-chain more than one lighter-rated one or you can overload the first one.

Running everything from one socket is also the safest from a shock hazard point of view as all the equipment earths will be connected to a single mains earth, so you can’t get a live-to-earth fault between two separate supplies.

Remember to fully uncoil any reel-type extension cables even if you don’t need the length - a coiled reel can overheat and melt when the current draw is high, I have seen this happen to a band!

shufflebeat

Wise words from ICBM.

I would add that the “star” arrangement described will also provide some protection from stray hums caused by earth loops.

I’ve done lots of gigs from 1x13a socket using 4-5 speakers which claim 1000w. They’re not and it’s fine.

Sporky

allen said:

A 13 amp socket at 240v is theoretically (13 x 240) 3120 watts. However, I realise that a socket is not normally expected to do that

They are. To meet the standard they must be capable of passing 13A continuously for an indefinite period of time.

I think (but am not 100% sure) they actually have to be capable of 15A.

allen

Thanks!

ESBlonde

Do consider lighting too! If some lighting is to share your power, it will need to be considered. That said many modern LED fixtures have decent output for relatively low current draw. Old incandescent lamps draw significantly more current.

flying_pie

I always assumed that if you're not a big enough band to have a dedicated stagen and lighting crew then you don't need to worry about it

Unless, of course, you're playing the Dog and Duck with the lighting and pyrotechnics rig that Rammstein uses, but that would be a bit silly

jeztone2

ICBM said:

One 13A socket is plenty for that - those figures are peak draw not average too.

The best way to do it is with one heavy duty proper 13A-rated 4-way extension, and then four more plugged into that, which can be lighter rated, giving a total of 16 outlets. Don’t daisy-chain more than one lighter-rated one or you can overload the first one.

Running everything from one socket is also the safest from a shock hazard point of view as all the equipment earths will be connected to a single mains earth, so you can’t get a live-to-earth fault between two separate supplies.

Remember to fully uncoil any reel-type extension cables even if you don’t need the length - a coiled reel can overheat and melt when the current draw is high, I have seen this happen to a band!

This!!!!!!

allen

Thanks again everyone. Gig went well, nothing went bang and the lights stayed on.

Keefy

allen said:

Thanks again everyone. Gig went well, nothing went bang and the lights stayed on.

Glad all was well. Couple of recollections from a function band I used to play with:
(1) BL was fond of daisy chaining mains extensions. He would switch on the stage lights with his toe and the resulting dip in voltage would cause a ‘brown out’ which would reset my Roland guitar synth to patch A01 (piano). The first time this happened I thought my GR30 had died!
(2) We once played a private party on a farm trailer in an open barn. A 4th wall had been built from hay bales. If someone had dropped a tab end we would all have been toast. For reasons unknown, someone put a meter on the single 13A socket that everything was plugged into - the reading was 19A!

Supportact

Played a pub gig recently and during soundcheck I had to point out to the sound engineer that there was smoke coming out of one of the multi plug power strips! (Belonging to the venue, not ours). 

Never seen that before.  I think the wiring at the venue was a bit suspect, it looked to me like they'd bodged together a few extension cables rather than have sockets installed in the appropriate places.  Anyway,  the power strip got removed and everything else continued without fire or electrocution. Not ideal though. 

Danny1969

Supportact said:

Played a pub gig recently and during soundcheck I had to point out to the sound engineer that there was smoke coming out of one of the multi plug power strips! (Belonging to the venue, not ours). 

Never seen that before.  I think the wiring at the venue was a bit suspect, it looked to me like they'd bodged together a few extension cables rather than have sockets installed in the appropriate places.  Anyway,  the power strip got removed and everything else continued without fire or electrocution. Not ideal though. 

That normally happens because someone has spilt beer or some other liquid into it and that conducts with resistance so gets hot rather than blowing a fuse.
In general our mains arrangement in the UK is pretty safe compared to other parts of the world. 

Supportact

Danny1969 said:

Supportact said:

Played a pub gig recently and during soundcheck I had to point out to the sound engineer that there was smoke coming out of one of the multi plug power strips! (Belonging to the venue, not ours). 

Never seen that before.  I think the wiring at the venue was a bit suspect, it looked to me like they'd bodged together a few extension cables rather than have sockets installed in the appropriate places.  Anyway,  the power strip got removed and everything else continued without fire or electrocution. Not ideal though. 

That normally happens because someone has spilt beer or some other liquid into it and that conducts with resistance so gets hot rather than blowing a fuse.
In general our mains arrangement in the UK is pretty safe compared to other parts of the world. 

It could have had some beer in it, but I'm suspicious of it because I noticed the power strip had gaffer tape wound round one end, so presumably previously damaged. Also it was plugged into another power strip hanging out of a wooden seating panel,  so you couldn't see where that was plugged in.  All in all looked a bit iffy.