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Minimum Voltage at incoming supply point

FlyWheel
Retired now and not up to date with reg’s since 16th. Helping advise a friend. Currently they have 100amp single phase supply and whilst the no load voltage is up at around 238 volts, as the circuit is loaded, voltage drops off substantially. Even with a load of 50 amps, ie, half the supply fuse rating, voltage is slightly below the -6% limit, at around 215 volts, further load simply pushes voltage significantly lower, and by extrapolating measured data, it would be nearer 170 volts with a load of 100 amps, is this acceptable? I plan measuring Ze and pfc this week as a guide perhaps to supply loop impedance and, which I suspect must be causing this excessive drop. I’m aware of the ESQCR reg’s although need to update myself, but are there any other regulations that apply?

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    Yes, same venue, and I also slotted in on some of their free air con and refrigeration courses there, but heat pumps were, as you say, still in their infancy.
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    That last post should have ended with doors and windows, I blame predictive text. But the floors may need insulating.


    One of the things I picked up on at the ASHP seminar was that you need to install a priority heating and hot water controller.


    There was one on the gas central heating system in our house wh we bought it, the old gas boiler didn’t have enough umph to heat the hot water cylinder and the radiators at the same time, so you had to switch the controller to tell it which you wanted heating first, so if you set it to heating the radiators the hot water cylinder would not be heated at all until the radiators had got the house up to temperature and the central heating thermostat was satisfied.


    The ASHP manufacturers said you may need to do the same with the heat pumps.


    Loading shedding and priority switching won’t solve the voltage drop issue, but might have to be considered as part of the long term solution.


    Andy Betteridge
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    The house in question is big enough and complex enough to have its own BMS system, and if it were mine, I'd have one, as a priority, and yes, it does have underfloor heating, mostly from house heat pump warmed water, but I notice system does have a 16 amp immersion in the storage tank too, and it's on auto!

    I don't know how familiar you are with refrigeration systems, but I'd be worried about just how the evaporator superheat temperature in a pool application, could possibly be high enough in the very cold weather to boil off refrigerant before it gets back to compressor. Ah, think I’ve answered part of my question that I asked on the other thread, I’ll give that some further thought. Have just emailed Mitsubishi to see if I can get some pool application data from them. Now what was the original question in this thread?!

  • Former Community Member
    0 Former Community Member
    Now what was the original question in this thread?!


    Why did the owner spend so much on the house and pool, but thought that the associated cost of getting an upgraded supply for the luxuries wasn't worth it?........


    Regards


    BOD
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    The farce continues. 

    Regards, UKPN.
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    Ah, but they did consider this, and even formally asked for an upgrade to 3-phase, at least 10 months ago when they first considered installing a pool, and paid a massive sum on account to get it, but perhaps with not the best advice for their installation overall, and that's one of the aspects that I'm now looking at for them,
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    When I spent the day at the manufacturers seminar they didn’t actually tell us you may need priority switching between water and space heating, it was an answer to my question asking why the demonstration unit they had set up had priority switching on it as I stood looking at it.


    The immersion heater should be set to come on automatically every few days to ensure that the stored water temperature is raised sufficiently every few days to kill bacteria in tank to prevent legionella and similar issues, because the stored water temperature won’t normally be high enough to do so.


    Andy Betteridge
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    Yes, water quality is a particularly important issue under G15 regulations, and I'll be taking that into account too via my heat pump post. It was also an important issue when I surveyed some major London hospitals, and I saw many examples of potential  breaches of the these regulations, particularly in their HVAC systems.Good point though in relation to why immersion would be on automatic on this heat pump installation, so thanks for that. Great this site, some real good advice coming through.
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    I went out into the countryside today had a lovely time but back to business I saw a couple of those little transformers feeding some DNO control equipment the tx was or at least looked like it was smaller than the insulators on it. Also I saw what I thought was a capacitor bank on an 11Kv line  not seen it before is this a new thing ?
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    Actually going back to the original question,  if a new three phase supply is installed then presumably the voltage drop issue would be resolved and the customer would not end up with droopy voltage on all three phases.


    Andy Betteridge

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