electric storage heaters

[rogerorkney]

hello,

i am considering 4 storage heaters for a one bedroomed flat.
combined kW for the heaters will be around 9kW.

should this be a ring circuit or a radial cicuit
cable to use
mcb to connect to

thanks
rog

 

[andy]

lot of power there.... do you have economy 7?

these should all have their own radial, with appropriate MCBs (probably 16A) and fed form their own CU. if you dont have E7, and still want to do it, take a feed from main CU using 10mm² and use a 50AMCB/45A fuse

Expect high electric bills tho

 

[rogerorkney]

so each heater needs its on own cable, the largest heater is 2.7kW.
if i run a 10mm cable to a seperate cu from a 50amcb.
what size cable from each heater will suffice and to what size mcb.

if i speak to the electricity company, i can get a "white meter" and this should save me money?

 

[Qedelec]

so each heater needs its on own cable, the largest heater is 2.7kW.
if i run a 10mm cable to a seperate cu from a 50amcb.
what size cable from each heater will suffice and to what size mcb.

1.5mm on a 16A MCB for each storage heater.

 

[rogerorkney]

thanks very much guys

 

[Lectrician]

I would go 2.5 with out a doubt. You need to ask for an economy seven tarrif and meter - this will then switch your heaters on and off at the cheap rate.

 

[rogerorkney]

to get economy seven , do they put in a second meter for that?
how much does that cost? roughly

 

[andy]

to get economy seven , do they put in a second meter for that?
how much does that cost? roughly

yes, they add a second meter, with timer (so it only give power during cheap times). if you get a 2nd meter, this will feed the CU for heaters

 

[Adam_151]

I would go 2.5 with out a doubt.

Yeah me too, its weird you can do the cable calcs and find 1.5mm is fine, but it feels 'wrong'

 

[Lectrician]

And probably would be with grouping taken into account

On smaller heaters I would say it would be ok - still would prefer 2.5!




The DNO will usually fit the new meter and teleswitch/timeclock for free on demand of your energy supplier. You need to ring them to find out.

The day rate lecky is charged at around 10p per unit, and the night units (used by the heater to store the heat) is around 2p a unit. Foolish not to have econ7 installed if you are having storage rads!

 

[crystal ball]

Assuming you are all electric, it will be worth getting a timer on your immersion heater to heat your water during off peak times

 

[kai]

On economy seven, it's well worth investing in a maxistore type of hot cylinder, with two separate elements in, the bottom one on economy seven supply, and the top backup element on the more expensive standard supply.

The maxistore cylinder is very well insulated, so that you should be able to heat most, if not all your water at the cheap rate, the top element being used as a backup, in case you sometimes run low on hot water in the day.

 

[Qedelec]

I would go 2.5 with out a doubt.

Yeah me too, its weird you can do the cable calcs and find 1.5mm is fine, but it feels 'wrong'

Funny you should say that, as when I wrote it I put 2.5 then thought "is that overkill" and changed it to 1.5. I have seen both and have never had anyone explain why. I agreed it 'feels' wrong with 1.5 but the calcs say yes.

 

[rogerorkney]

On economy seven, it's well worth investing in a maxistore type of hot cylinder, with two separate elements in, the bottom one on economy seven supply, and the top backup element on the more expensive standard supply.

The maxistore cylinder is very well insulated, so that you should be able to heat most, if not all your water at the cheap rate, the top element being used as a backup, in case you sometimes run low on hot water in the day.

spoke to scottish hydro today, after 45 minutes and six different people passing me from pillar to post i have arranged a load test and a then installation of a domestic energy saving meter (economy 7) in the next few weeks!

so i am going to order a volex cu and 5 16a mcb's
this is for the 4 storage heaters and also i have a titan pressurised direct water heater using 3kw.

that should do the trick.

one thing, will the meter they install only work during the night?
if the water heater needs heating during the day, will i need a seperate power supply from my other meter? or does it just charge more for times during the day?

 

[Steve]

The immerison heater will only work at night. many have a top-up heater in the top of the hot water cylinder, which is connected to the normal supply. dont know about the heater you describe though.