This guide focuses on choosing generators, but much can also apply to a venue who are also asking for your requirements. We've tried to keep it simple, but it actually really can't be simplified much further without loosing important details.

Organising power for your event is probably one of the most 'technical' aspects of event planning.

The reason behind this is simple. Too small a generator will result in power failures, equally too large a generator will mean wasted money on hire, fuel and for the operator increased maintenance.

The goal then is to find a generator suitable for the job. But where do you start?

First of all, I'm afraid we cannot escape some technical background, so lets quickly look at how power is measured -  and remember, the goal quite simply is to establish the total load of all appliances to be used at any one time.

The power requirements of any applicants are measured in Amps or Watts, so lets start there.

A watt is simply unit of energy. For example, a kettle may consume as much as 3000 watts. This can also be written as kW. 1kW = 1000W. So that kettle would be 3kW. This is about the most that can be drawn from a UK 13Amp socket.

A Watt is actually made up Volts and Amps. In the UK we are approximately 230 volts. So 230 x Amps = Watts. In our kettle above we can flip the equation to Watts/Volts = Amps. 3000/230 = 13Amps. This is why we don't have 4kw Kettles on our UK 13 amp plugs - the fuse would blow!

The reason you need to know the above is generators are usually supplied with 16, 32 or 63 Amp (and even higher) outdoor "ceeform" sockets. 

To make matters slightly more confusing, Generators are primarily measured in kVA which is similar to kW but not quite the same. To make life simple, you won't go wrong if you work along the lines of 1kVA = 0.8kW conversely 1kW = 1.25 kVA

Ok now we have done the technical information, where do you start with event power?

Catering For the average event, Catering usually consumes the most power. If you are using an experienced caterers they will have been asked this question before, and should be able to quickly provide their requirements. Often it may be they use special out door rated plugs, these most commonly come in 16 and 32 Amp sizes.

Lighting Lighting was once the biggest consumer of event power, however as technology has moved on, lighting has become more efficient, and with the wide use of LED's the load has dropped significantly. To add to this, some fixtures like our uplighters are internally powered and add nothing at all! Most general Marquee lighting is quite sensible and won't even be 1kW ~4 Amps.

DJ/Band sound and lights This can vary a lot. All said and done its probably easier to ask the DJ/Band how many 13amp plugs they usually use. As a note however, some of our own big indoor events will run from two 13A sockets, so we would be surprised for example if any DJ/Band asked for three, and certainly most 'normal' events should be fine with just one.

Outside toilets These will usually be either on a 16 or 32 Amp supply. The hand dryers and water heaters can consume a lot of power - but it does vary a lot. Some use hand towels, and only cold water. Those would require very little power - so its best to ask. The fact they ask for 32 Amp supply does not mean they may use it all - and its good to know this, consider also (!) from a very practical point of view, toilets are generally used mostly after the catering has finished!

Misc suppliers, Photo booths, and so on - it would be rare that anything else would require more than a single 13A supply. Candyfloss machines and Popcorn makers can consume quite a bit, but rarely more than a 1-1.5kW each.

Finally once you have added all this up, multiply by 1.25 to convert to kVA and finally add 20% for headroom, so that you still have some reserve capacity.

Lets recap with a practical example:

You ask your suppliers for their power requirements.

Catering asks for 32amp supply, but confirm they are only have a total of 7kW of appliances.

DJ/Band asks for one 13A socket.

Marquee lighting requires 1 16amp socket, but you are told, only uses 1kW.

Outside toilets require 16 Amp supply, but uses 2.5 kVA (Caution! Already kVA, add this after the rest of the calcs are done!)

Total:

Catering 7kw
DJ 3kW
Marquee Lighting 1kW
Total 11Kw
11x1.25 13.75kVA + 2.5kVA for toilets
Now lets add some spare capacity:
16.25*1.2= 19.5kVA (1.2 is 20%)

Final total 19.5kVA (Still with us I hope?!!)
Which fits perfectly with our 20kVA Generator!

Apologies again with how technical this is. That being said, it is very important to get right. All this information here is EXACTLY what we need to know when providing power for you. Much of these we can help with, but it makes life so much easier if you know what you need to ask your suppliers along the way. With this information we will turn up with everything you need giving you and us an entirely stress free experience, with no nasty surprises!

As always, if you have any questions, give us a call. We are always happy to help and discuss your plans.