Lot 20 Central Heating Wows and I am Stuck and Need Help

Postby nargos » Sat Feb 10, 2018 1:44 pm

I just lost one of my electric storage heaters and so I have been looking for a replacement. I had planned on putting in fan assisted models when I got to this stage so have been extending the ring main to provide the 24H power. The government and EU have now enacted Lot20 which means that all electric storage radiators need to have an on-demand power so they now incorporate an 24H powered electric heater panel of around 1.1KW. I have 3 radiators and so this would mean an additional 3.3KW load on too the 32A ring main (which I understand can take a max of 7KW). Clearly this is not safe and I am not content to just not use the boost function as I will sell the home on some day and that is not going to end well.

So I need a new 24H circuit to drive the power for the boost. Looking at my consumer units there are three things I can see.

1. It appears that the 24H power and 7H power run off separate phases. (I will confirm for myself tonight)
2. There are circuit beakers for 130A already plugged into the two 24H consumer units (One is the main and the other is the shower). The extra 3.3KW will need another 16A circuit bringing the total for this too 146A which is 46A on the wrong side of uncomfortable.
3. A single phase takes only 100A.

So I have looked too see if I can find a Residential Demand Controller as there are 24H circuits which can be shed if the load was to rise above 100A. Namely the boost for the hot water tank, the shower and the boost to the radiators them self's which counts for 72A, which leaves me well inside the 100A max load.

Unfortunately there does not appear to be any such device on the UK market.......

So I can not believe that there is not a solution to this as I have a small 2 bed flat. Does anyone have any advice?
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Simply Build It

Postby ericmark » Sat Feb 10, 2018 11:33 pm

When the 13A socket and ring final was designed at the tail end of world war II it was designed to be used to heat the home, However things have moved on since then, the pins have protective sleeves on them which reduces the heat removed from the fuse, and the cable was 7/0.029 and now it is 2.5mm (7/0.0243) so not as good today as when first introduced.

The idea of E7 is the heavy load is when we are not using any other power in the house, to run the heaters at same time as washing machine, dish washer, tumble drier, cooker, and instant showers is maybe a little too much.

However it is all down to design, and designing over the internet is not really the best option. I go on holiday summer and winter in a caravan, it has a 16A supply, the electric does fridge, hot water lights, central heating and battery charging as well as socket outlets, I have not tripped power due to overload.

My hot water is stored, not instant, and no washing machine, oven is gas and hob is a single area induction hob, but the flat has a 100A supply not 16A so although a large house may have a problem there should not be a problem with a flat.

Electric heaters are actually rated as to how efficient they are, at first this seems daft, 3 kW in must mean 3 kW out, however it is the time taken to heat the area and time which the area is used for which alters efficiency, so 1 hour to heat room ready for use, room used for 1 hour, heater 50% efficient, so a fan heater is much more efficient than a storage heater because it heats room fast and so is not on as long as the storage heater.

Using a water heat store can change this, but with premises used 24/7 then a good off peak heater can work, but where the user only gets home at 6 pm and is out to work most of the day, simple fan heaters are likely better than storage heaters.

So wiring can be installed to work what ever you want, But as to if cost is worth it, that is another question, I have only lived in a flat once, and I know my electric bill rocketed in the summer, running an AC is not cheap, OK I was in Hong Kong, but I was out during the day so I allowed flat to get hot in the day, and only cooled it when I got home. So my bill was not that high. I also could not close kitchen door, fridge/freezer was too big, that also increased cooling bill as had to cool kitchen.

So there really is not a simple once size fits all answer.
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Postby nargos » Sun Feb 11, 2018 3:47 pm

Cheers Mark.
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