Help- Storage heaters

Discussion in 'Electricians' Talk' started by DIY'er, Dec 11, 2003.

  1. DIY'er

    DIY'er New Member

    As a (I hope) responsible DIY'er I do hope someone can advise me on a possible heating issue.

    We have recently moved into a 6yr old 2-bed house with a country cooker oil heater more or less in the middle of the ground floor. This heats itself and one radiator, which is in the shower room. This works OK, but means that the 2 downstairs room at the 2 ends of the house get a bit nippy in cold weather.

    I have checked out the wiring - there are 2 x 32A ring circuits, one handling one side of the house (ground and first floor) and one to the other. There are no storage heaters at present & these ring mains are lightly loaded -occasional 2kW convector in a bedroom.

    What are views on me having one 2.55kW storage heater fitted via a fused switch (using heat resistant flex of course) fitted to each of these 2 ring mains? Common sense tells me it would make use of these 2 circuits at night, & only use up a third of the capacity of each (when there is virtually no power draw anyway).
    It would be an awful lot easier than cutting channels right through the house back to the consumer unit to radially wire each one separately without jeopardising safety. Or would it?

    The consumer unit is 80A with a 30mA RCB fitted. The meter is of a dual type which records all full price elec on one reader and cheap rate on another clock.

    Thanks in advance for any advice.
     
  2. unphased

    unphased Screwfix Select

    Hi DIY'er

    The rules for connecting storage heaters are that you should run each one on its own radial circuit with its own fuse. This is because storage heaters are quite a high load (2.55kW is just over 11Amps). It is usual to connect the storage heater using heat resistant 2.5mm2 flex (as you correctly stated) to a switched fcu fitted with a 13A fuse then you want 2.5mm2 T&E feeding this direct from the CU. Normally, as you have economy seven available you would have a separate CU wired to the separate meter for this so you get maximum benefit using cheap juice to charge the heaters overnight then they do their heating during the day. Use a 16A MCB for each heater. You must ensure that the storage heater circuits are wired up on the cheap rate meter or they will just use the expensive stuff.

    RSS
     
  3. DIY'er

    DIY'er New Member

    Thanks for your reply.

    I've checked to make sure & we must have a more unusual meter. There is only the one CU - everything goes through it. What happens apparently is that the elec provider switches over to the low tariff meter every night using an electronic radio teleswitch, so that ALL power used in the property between midnight & 7am is recorded on this one, then at 7am they switch it back to the daytime tariff & record on the other meter - there are simply two separate counters, one below the other in the meter box, which are activated according to the time of day.

    This would mean that we would be OK connecting one 2.55kW storage heater via a switched FCU into the 32A ring main for overnight charging at the low tariff, wouldn't we?
     
  4. unphased

    unphased Screwfix Select

    The meter/tariff is simpler...I cant sanction the connection of the storage heater to the ring main I'm afraid as it is against the rules. You really should run on a separate radial as explained.

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  5. DIY'er

    DIY'er New Member

    Thank you for your advice. It is much appreciated and I will of course take it as a "responsible DIY'er."

    However I would like to complain about the Rules. <u>Why</u> can't this be done, in view of the fact that I can (and have from time to time) connect up 2 x 2kW convector heaters onto the same ring main using fused plugs via a timer to heat up each end of the house between 5am and 7am? Surely this can't be anything like as safe as a fixed output heater. Or do the people who make the Rules have a vested interest in selling more full price electricity rather than cheap rate electricity?
     
  6. unphased

    unphased Screwfix Select

    :) well rules are rules, however, the reason for the storage heaters being on a separate circuit is that they are pulling quite a high current demand (for one appliance) for a long time (ie overnight) and if you were to have two or three of these on a ring then this could potentially cause problems on the circuit...however I can see your point re just one...similar thing with convector heaters but they tend to switch on and off intermittently as the thermometer reaches temperature and they dont place such a constant demand on the circuit...I am sure supersparky and friends can beef up this a little..watch this space!
     
  7. supersparky

    supersparky New Member

    could...but UP has gone as far as needs be, you are a diyer(no dis respect) you only need to know the whys and hows of your profession, let us worry about them for electrics, we are paid to! and you can see how much we argue on these forums already...its even infected the plumbers....

    BR
     
  8. professional

    professional Member

    Unless you have the old `Economy 7` meters fitted, you will find that, even though you may have two consumer units, <u>all</u> of the electric that you use during `off-peak` hours will be charged for at the lower rate! So, in theory, you can wire a night storage heater either straight off the n/s consumer unit or off a ring on the `standard` consumer unit with a suitable timer. However, due to the charging time involved, you could only do this with a relatively small heater (i.e. 1.7kW or less).
     
  9. seavigil

    seavigil New Member

    When we moved into our house 10 years ago I got curious about 2.5mm cable running around the loft.
    After a bit of asking around of the owners from new and previous owner, I found out that they had 6x 2 kw convector heaters set into the walls as the only form of heating these had since been removed in favour of gas CH and the holes left in the wall borded over. The wiring was going up and down cavitys and across the loft space. So I pulled out all of the old cable as it wasn't attached to anything at either end. However I have never found out where power came from since the 4 way consumer unit is fully occupied and looks original as does the meter box ( no connector blocks or old screw holes on the board. I can only assume they were on the ring fuse!!

    We are just about back to the original paintwork on the walls now and no evidence of second CU (filthy job chasing channels and sanding down plaster)

    DJW
     
  10. sheddyeddie

    sheddyeddie New Member

    thank you for that
     

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