What loads are expected to be used ? Just power tools, a few lights and a kettle ? Or well equipped welfare facilities with electric space heating, electric cooking and electric showers.

For the former, a single phase 60 amp supply should suffice, for the later is more likely to need 100 amp single phase.

wil there be electric cement mixers / demolition hammers etc and how many people are working at once?

A big site with 6 large teams one per house, at work together all going at full blast all day, may need 3 phases. 
If it is a core team of  3 guys at a time plus occasional specialists doing all 6 but one after the other at a sensible pace, then actually the no of bungalows is not so important except for the duration, and as per Broadgage's answer, the biggest single load is the tea making and a microwave... So, how big is the site hut ;-)

Mike

Hi ARL02. My own experience of this is that the electrical supply for the temporary cabins varied depending on the project and the existing infrastructure. For a renovation project of an existing building, we provided three separate single-phase 32A supplies for the cabin, the office, and the toilet block. For a hospital extension project, we provided one three-phase 200A supply for all the cabins and shower blocks. The specification of the electrical supply was usually determined by the principle contractor who was responsible for the CDM.

How long is a piece of string?

"Bungalows" implies modest-sized dwellings. I would expect that the work will be staggered, and as Mike says, it would be the same for one bungalow as six. I suspect that the cost of a 100 A (SP) supply would be the same as for 60 A on the basis that the actual cost of the service cable is a very small proportion of the total. If that is the case, the supply might as well be 100 A.

Hi All,

Thanks for reponses really appreciate the adivce.

I have attached the site drawing to answer a few questions

There is 6 small bungalows being built, they would be going from house to house would imagine there would be no more than 6-8 on site at one time.

My first impression would be the same as broadgage  with a few tools and ancillary power for the site cabin.

I think then for what is really a single team of workers.  I'd suggest you ask for the DNO to  quote for 100A and also 60A 1 phase - unless it is vastly more go for 100A - I suspect it would be the same cable in both cases and only the fuse changed. Might be worth trying to get the area engineer on the phone if you can but these days with web portals and all it is far harder to reach the right bod, as the 'have a nice day' team tend to get in the way rather.

You probably want it to terminate in an isolator ( A REC 2 would do in a meter box) so you can re-configure things if need be without main fuse removal. (or even coil up cables and put them out of reach at the weekend if it is that sort of area where theft maybe an issue.)

Mike,

When building a single dwelling it's common the the DNO "builder's" supply to be re-used as the permanent supply to the dwelling when complete - it might involve a move of the cut-out/meter at some stage, but the main cables from the street and connections into the the existing main can remain unchanged - usually with a corresponding saving in overall costs. It's unlikely the temp supply will need to be larger than the permanent one - so the initial request relates more to the final building than the builder's immediate needs. So +1 for taking to the DNO - but in the context of what will be needed eventually as well - it may well be cheaper and quicker in the long run.

Note that some DNOs offer 80A supplies as standard these days and may charge a lot more if you ask for a 100A one - just something to keep in mind if you don't really need the extra 20A.

I couldn't zoom in on the plan to see the details - but are those detached garages towards the top (North) of the plot? Just wondering if they'll need EV charge points...?

   - Andy.

It seems that the yellow Es on the map will be the EVCPs. More detail here.

Somehow I struggle to see the tenants of such modest homes driving EVs any time soon.

I don't see why.  Assuming the stereotype older person down-sizing from a larger house, they may well have enough money for a decent second-hand electric run-around.  If they only do short journeys, it's less hassle than a fossil fuel car.

Perhaps not initially, but the need to charge EVs is very likely within the life of the homes and the electricity supply should allow for this.  Presuming a common 7kw charger that suggests a 100 amp supply unless other loads are small and expected to remain small.

An EV charger is a long hour load and no diversity should be applied. So that only leaves about 70 amps for general use.