Newbuildnewbie Posted March 15, 2022 Share Posted March 15, 2022 Hi We're building on a plot previously occupied by a bungalow which has a single phase supply with 100amp fuse We have an ashp (16kwh) and are asking UKPN for permission to install but our electrician is telling us that allowing for electric car point in the future etc that we could be looking at a maximum demand a little in excess of 100amps Has anyone experienced this and know what UKPN will say? I'm guessing these calculations are made on an abundance of caution because ashp are supposed to be efficient etc so won't run at full whack and if we did have electric car point in future we would probably charge at night etc so I don't really want to pay to upgrade to three phase if not really necessary given the single phase supply already there currently. Any thoughts appreciated! Link to comment Share on other sites More sharing options...
Simon R Posted March 15, 2022 Share Posted March 15, 2022 3 minutes ago, Newbuildnewbie said: we could be looking at a maximum demand a little in excess of 100amps Maybe if you ran everything at once, but in the real world it's not a problem. We have a 100A supply and a 32A EV charger + Induction hob 20A + 16A cooker +++++ but in practice we never get anywhere close to 100A. 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 15, 2022 Share Posted March 15, 2022 20 minutes ago, Newbuildnewbie said: Hi We're building on a plot previously occupied by a bungalow which has a single phase supply with 100amp fuse We have an ashp (16kwh) and are asking UKPN for permission to install but our electrician is telling us that allowing for electric car point in the future etc that we could be looking at a maximum demand a little in excess of 100amps Has anyone experienced this and know what UKPN will say? I'm guessing these calculations are made on an abundance of caution because ashp are supposed to be efficient etc so won't run at full whack and if we did have electric car point in future we would probably charge at night etc so I don't really want to pay to upgrade to three phase if not really necessary given the single phase supply already there currently. Any thoughts appreciated! You'll be very surprised what will run off a 100A supply. Do not forget about diversity when calculating your max loads ( but I assume your sparky would have already done that ). If you are really struggling, you could always fit a load-shedding relay which would stop ( for one eg ) the induction hob and the EV charger being on simultaneously. That would bag you a spare 7kW. Link to comment Share on other sites More sharing options...
SteamyTea Posted March 15, 2022 Share Posted March 15, 2022 8 minutes ago, Nickfromwales said: you could always fit a load-shedding relay Are these commercially available? Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 15, 2022 Share Posted March 15, 2022 (edited) 6 minutes ago, SteamyTea said: Are these commercially available? https://www.omnical.co/products/hager/ed183/2295794 It was a domestic sparky that made me aware of them tbh. Well he was domestic and light industrial iirc. Edited March 15, 2022 by Nickfromwales 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted March 15, 2022 Share Posted March 15, 2022 8 minutes ago, Nickfromwales said: https://www.omnical.co/products/hager/ed183/2295794 It was a domestic sparky that made me aware of them tbh. Well he was domestic and light industrial iirc. Had a quick look, can't see how they work, the Hager link gave me a foreign 404. Shall have to research more later. Somewhere, I have a current based switch, was going to put it on my hob supply to turn on an extractor fan, but still not got around to it. I think it could be used with another one to set up as an logic OR, or AND. That may a cheap solution. Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 15, 2022 Share Posted March 15, 2022 I'll be honest I've never done one, but was explaining a problem to a sparky and he mentioned it to me. I thought it was a handy get-out-of-jail card when tipping the max load scales. @ProDave @Onoff ? Link to comment Share on other sites More sharing options...
SteamyTea Posted March 15, 2022 Share Posted March 15, 2022 4 minutes ago, Nickfromwales said: I thought it was a handy get-out-of-jail card when tipping the max load scales. Struggling to find details, but it may just be a self resetting breaker. I cannot see how it senses the total load in the building. May be wrong. Can get them for 13 quid, shall let you buy one and see what you can find. Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 15, 2022 Share Posted March 15, 2022 Just now, SteamyTea said: Struggling to find details, but it may just be a self resetting breaker. I cannot see how it senses the total load in the building. May be wrong. Can get them for 13 quid, shall let you buy one and see what you can find. I'll try and speak to my friend and see if he can state what he did / how etc. Agree, there's the square root of feck all info jumping out at me either. Link to comment Share on other sites More sharing options...
ProDave Posted March 15, 2022 Share Posted March 15, 2022 10 minutes ago, Nickfromwales said: I'll try and speak to my friend and see if he can state what he did / how etc. Agree, there's the square root of feck all info jumping out at me either. I assume with the low current rating, it is used with a current transformer. And the NC contact would hold a contactor energised (wasteful) that would be released and turn off a big load if the max current was exceeded. Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 15, 2022 Share Posted March 15, 2022 1 minute ago, ProDave said: I assume with the low current rating, it is used with a current transformer. And the NC contact would hold a contactor energised (wasteful) that would be released and turn off a big load if the max current was exceeded. Yes. A last resort, but an option to get someone out of the cack maybe. Link to comment Share on other sites More sharing options...
ProDave Posted March 15, 2022 Share Posted March 15, 2022 1 minute ago, Nickfromwales said: Yes. A last resort, but an option to get someone out of the cack maybe. Probably a tick box to get the DNO to accept it and nobody cares or will test if it actually works. Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 15, 2022 Share Posted March 15, 2022 1 minute ago, ProDave said: Probably a tick box to get the DNO to accept it and nobody cares or will test if it actually works. Yup, lol. Link to comment Share on other sites More sharing options...
Adrian Walker Posted March 15, 2022 Share Posted March 15, 2022 1 hour ago, Newbuildnewbie said: Hi We're building on a plot previously occupied by a bungalow which has a single phase supply with 100amp fuse We have an ashp (16kwh) and are asking UKPN for permission to install but our electrician is telling us that allowing for electric car point in the future etc that we could be looking at a maximum demand a little in excess of 100amps Has anyone experienced this and know what UKPN will say? I'm guessing these calculations are made on an abundance of caution because ashp are supposed to be efficient etc so won't run at full whack and if we did have electric car point in future we would probably charge at night etc so I don't really want to pay to upgrade to three phase if not really necessary given the single phase supply already there currently. Any thoughts appreciated! Smart EV chargers detect the max current and will throttle back since thy will be the biggest load and and can wait - dinner can't 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted March 15, 2022 Share Posted March 15, 2022 9 minutes ago, Adrian Walker said: Smart EV chargers detect the max current and will throttle back since thy will be the biggest load and and can wait - dinner can't It can where I work. Link to comment Share on other sites More sharing options...
Onoff Posted March 15, 2022 Share Posted March 15, 2022 28 minutes ago, ProDave said: I assume with the low current rating, it is used with a current transformer. And the NC contact would hold a contactor energised (wasteful) that would be released and turn off a big load if the max current was exceeded. Also called an intensity relay that: The priority relay is designed to prevent overloading of the building's installation due to the simultaneous activation of many large power consumers (e.g. a flow heater).The coil of the ED183 priority relay is connected in series to the receiver with priority.When this receiver is switched on, an output contact opens and the switch on the receiver switches off without priority. Bioenergy switch: • automatic disconnection of the supply voltage (phase cable) from the receiver or group of receivers, in the case of detection of no load, • automatic operation - disconnection of the power supply for 3 seconds when detecting no load or switching off the receiver, monitoring of the state of the powered circuit and re-application of the supply voltage after detecting that the receiver is turned on (electricity consumption) • manual operation (switching by means of a switch) - the voltage is supplied to the receiver continuously, without monitoring the load condition, • parameters of the output relay: 1NO 16 A 250 V AC AC1, • voltage monitoring the state of the receiving circuit: 15 V DC. also suitable for electronic flow heaters Output: 1 NC contact, 250 V / 1 A AC-1 rated current range: up to 39 A Relay operating current: 3.1?And?5.7 A flow heater: up to 27 kW Link to comment Share on other sites More sharing options...
SteamyTea Posted March 15, 2022 Share Posted March 15, 2022 6 minutes ago, Onoff said: relay is connected in series to the receiver with priority Does that mean there is some other kit that goes with it? Link to comment Share on other sites More sharing options...
Onoff Posted March 15, 2022 Share Posted March 15, 2022 (edited) 32 minutes ago, SteamyTea said: Does that mean there is some other kit that goes with it? Best I can find at the mo. Relay on the left translates as "receiver priority" on the right "no priority". I'll try and find it in English Edited March 15, 2022 by Onoff Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 15, 2022 Share Posted March 15, 2022 1 hour ago, Onoff said: Best I can find at the mo. Sleep is for the weak. I want the answers on my desk by 08:00. 1 Link to comment Share on other sites More sharing options...
TonyT Posted March 15, 2022 Share Posted March 15, 2022 https://www.meteorelectrical.com/pub/media/catalog/product/file/Shower Boards_1452600737.pdf 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 15, 2022 Share Posted March 15, 2022 1 minute ago, TonyT said: https://www.meteorelectrical.com/pub/media/catalog/product/file/Shower Boards_1452600737.pdf We're getting there. It was showers in an HMO I think my mate was working on. Memory is shot to shit these days. Thanks for this. Link to comment Share on other sites More sharing options...
TonyT Posted March 15, 2022 Share Posted March 15, 2022 👍 Link to comment Share on other sites More sharing options...
Onoff Posted March 15, 2022 Share Posted March 15, 2022 Thinking about it my Triton Body Dryer has the same deal in it if you want to run it and a leccy shower from the same cable. 1 Link to comment Share on other sites More sharing options...
Gus Potter Posted March 16, 2022 Share Posted March 16, 2022 14 minutes ago, Onoff said: Thinking about it my Triton Body Dryer has the same deal in it if you want to run it and a leccy shower from the same cable. Delightfull.. thanks for the heads up Onoff. Sparkies use a term called diversity. @Carrerahillmay pop up and explain in detail how this works from the IEE regs point of view and the theory. But in summary I understand (I may just know enough to be dangerous!) that although the sum of all your appliances may exceed 100 amps they are less likely to all need maximum demand at the same time. Also, the fuse (100A) in the cable head is apparently called a sand fuse and does not blow with a short surge. Then often at the local sub station there is a 600 amp fuse. But if you have say one of these electric Ferarris that do ultra rapid charging at some 400 amps? you may be on a loser and need separate phases for example. Link to comment Share on other sites More sharing options...
Onoff Posted March 16, 2022 Share Posted March 16, 2022 Just now, Gus Potter said: Sparkies use a term called diversity. Beware the Christmas dinner effect! It's all gone pc now with regard to overcurrent protective devices and say RCDs on the same circuit. Diversity between devices in that context is now know as selectivity 😂 1 Link to comment Share on other sites More sharing options...
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