First off - never, never, EVER believe the first or second set of figures given to you by the catering company. When they want to serve 200 people coffee in one go they'll turn on at the same time as many 3kw machines as they need to.
Generally speaking, if it's a party tent then you'll need the following: House lighting (normally some shabby chandeliers that the tent boys put up), catering power, bar power, 2 x 16A for a band (at least - check). You might also need cloakroom power/lights, exterior lights and possibly a feed for some EM's if the tent co has put them in (or they might expect you to). Check too if the tent co are providing some heaters - they're normally diesel fuelled blowers but they have electric ignitors and stats.
By far the easiest way of doing this is to find your nearest rental company and buy in a whole shed load of rubber box IP distro and 16A artic/HR07 cable. PM me where you/gig is and I'll tell you where to shop! BUT, if you're doing this for love then you might not want to spend £££'s to hire in. The flip side is that a 10m 16A cable will probably cost you a quid to hire, but 10m of HR07 and a fe/male ceeform each end will set you back £20 for bits and half an hour to make. Multiply by 50 and...........
If you're booking the genny in yourself, or know where it's coming from, then see if they'll throw you in some distro and cable for free at the same time. Take care if it's a builders gen set, as it'll 1) do anything under serious load that it wants to, including spikes and dips galore 2) be bloody noisy and 3) may not have a set of lugs / red 32 or 63 ceeform outlet 4) RCD is probably shagged and 5) they won't have sent an earth rod with it.
Oh, and watch for RCD's tripping when everything gets damp overnight - better to leave it up and running! Also, if you end up with rubber box distro > various other sub boxes, they'll almost certainly have the same 30mA RCD's in them, so forget any notion of discrimination!
DO make sure you make a valiant attempt to get a decent grounding on an earth rod.
PM me if you want some more help!
