LSB Posted March 17, 2021 Share Posted March 17, 2021 Hello Our electric board UKPN has asked for our KVA requirements to complete their quote. I may have posted this previously, but I can't find the answer. This is for 2 * 32amp EV charging 3 * power showers 2 * cooker hobs 4 * ovens 4 bedrooms office with 6 computers plus 2 x printers 3 * TV's plus DVD etc Solar PV, 10 - 12 panels ASHP MVHR Cart-lodge / Garage / Large workshop Water Treatment plant 120m drive with lighting and electric gate at road side We have asked for 3 phase, which is available, but they want to know the KVA needs TIA Link to comment Share on other sites More sharing options...
TonyT Posted March 17, 2021 Share Posted March 17, 2021 Well 3phase 100 amp is a 70 KvA supply. 1 Link to comment Share on other sites More sharing options...
LSB Posted March 17, 2021 Author Share Posted March 17, 2021 3 hours ago, TonyT said: Well 3phase 100 amp is a 70 KvA supply. I know, but UKPN are asking me what KVA I need and although I've looked I don't understand the calculation to get this. I asked my sparky, but he's a bit slow on answering. Link to comment Share on other sites More sharing options...
PeterW Posted March 17, 2021 Share Posted March 17, 2021 kVA is (Volts (230) x Amps)/1000 Most houses have an 80A or 100A supply on single phase. Go to 3P and you can reduce that as long as you can get diversity on the phases and not have the issues of needing more than one phase in the house which needs to be very well designed. 3x80A would be plenty assuming House 1P, Cart lodge/workshop/outdoors 1P, EV chargers 1P So thats a 240x230=55kVA supply. Link to comment Share on other sites More sharing options...
TonyT Posted March 17, 2021 Share Posted March 17, 2021 (edited) kVAx1000 (divided by line voltage x root 3 Edited March 17, 2021 by TonyT Link to comment Share on other sites More sharing options...
LSB Posted March 17, 2021 Author Share Posted March 17, 2021 when I was talking the person I was talking to said similar, chargers 1p and workshop 1p except he wasn't sure that 1p would be enough for ASHP & MVHR & Solar PV. To be fair he was there to quote to replace our current oil boiler and said he would get the company sparky to help me, but I need to chase him. In our current house we have 1p in the house and 1p in the annex and 1p in the workshop / garage / stables etc. Link to comment Share on other sites More sharing options...
TonyT Posted March 17, 2021 Share Posted March 17, 2021 Are the power showers really electric? Link to comment Share on other sites More sharing options...
TonyT Posted March 17, 2021 Share Posted March 17, 2021 https://the-regs.co.uk/blog/?p=223 have a look at this to work out diversity foegwt about TVs etc loads are negligible be concerned about heating, water heating , cooking. ev charging Link to comment Share on other sites More sharing options...
TonyT Posted March 17, 2021 Share Posted March 17, 2021 (edited) Do you want 3 phase Ev chargers? Can you fit more than the standard 16amp single phase supply worth of PV on your roof/ ground mount? are we talking 10.8kW type Mira sport showers? what type of cooker hobs and ovens? will you be using 3 phase equipment anywhere? Edited March 17, 2021 by TonyT Link to comment Share on other sites More sharing options...
LSB Posted March 17, 2021 Author Share Posted March 17, 2021 9 minutes ago, TonyT said: Are the power showers really electric? final decision not made yet, I'm hoping to run from tank, but need enough hot water for 4-6 people so also at the least needs emersion, I'm hoping to get lots from solar Link to comment Share on other sites More sharing options...
LSB Posted March 17, 2021 Author Share Posted March 17, 2021 2 minutes ago, TonyT said: Do you want 3 phase Ev chargers? Can you fit more than the standard 16amp single phase supply worth of PV on your roof/ ground mount? are we talking 10.8kW type Mira sport showers? what type of cooker hobs and ovens? will you be using 3 phase equipment anywhere? my planning specifies 1 fast EV charger and 1 overnight, so I think the fast is 32amp. showers, not sure yet cooker is hob and 3 ovens as I cook and bake a lot so want main oven, second oven, baking oven (no smells) and grill. I will need to speak to hubby re 3 phase equipment, the workshop is his domain. what sort of things use 3 phase as he is up in the barn at the moment making a door for the storage shed. Link to comment Share on other sites More sharing options...
TonyT Posted March 17, 2021 Share Posted March 17, 2021 Fast chargers can be anything from 7 to 22 kW. You could have these loads programmed to come on, off peak so again it can minimise your load by careful time shifting. I have 7kW and it’s fine for my car. overnight charge - not sure what they Mean by that, but could be a granny charger socket on a 13amp socket? you really need to work out loads first to get an accurate basis for your design. 3 phase 100 amp would cope admirably but you could be paying over the odds for capacity that you won’t use. 3 phase 60 amp could be fine and like wise 3 phase 80 amp could fine. Link to comment Share on other sites More sharing options...
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