Cable for storage heaters

[shaggy]

We agree on the loading of a 3.4kw heater then. That was the point of my post; you can't plug a 3.4kw heater into a 13A socket. If you had a 2.5kw heater then you could do that, but if the heater had been sized wrongly then it may be upgraded to a 3.4kw in the future and someone may plug it into the socket without appreciating the loading. If all storage heater points are 20A cord outlet switches then you can fit any heater. I don't know why timers are mentioned because the heaters are already on off-peak supply anyway.

 

[juwelkeeper]

so if the storage heaters are rated 2.5 kw or below you could plug these straight in to a 13a socket .

 

[shaggy]

Not on the ring circuit, no. Each storage heater goes on it's own way in the CU. As I've said I don't think it's a good idea to use a socket anyway.

 

[ban-all-sheds]

malawihap has gone very quiet....

 

[plugwash]

so if the storage heaters are rated 2.5 kw or below you could plug these straight in to a 13a socket .

yes you could BUT

firstly there is the control issue (ie do you really want a seperate timer for every heater rather than them just switching with the off peak power)

secondly there is the power drain issue plug more than a few into a ring and you have overloading problems

 

[ban-all-sheds]

so if the storage heaters are rated 2.5 kw or below you could plug these straight in to a 13a socket .

yes you could BUT

firstly there is the control issue (ie do you really want a seperate timer for every heater rather than them just switching with the off peak power)

secondly there is the power drain issue plug more than a few into a ring and you have overloading problems

whats wrong with putting a plug on a storage heater?

 

[plugwash]

nothing wrong with putting the plug on in fact it will work fine

this method of connection has obvious advantages and disadvantages which must be considered

 

[shaggy]

I'm surprised at a pro like you giving this advice plugwash. Technically you can connect the 2.5kW load to the ring but with storage heaters it's not recognised as good practice. Surely you want to advise good practice and not just compliance with regs?

 

[plugwash]

why is using a plug synonomous with putting stuff on the ring

maybe its just me but i just think a plug and socket makes a nice easy to disconnect demarcation between fixed wiring and the appliance

btw im not a pro

 

[shaggy]

I was more critical of putting storage heaters on the ring and overloading. If someone can't afford to fit ch they may start to buy storage heaters one at a time, so where do they stop? Do they fit 1,2,3 or 4? They are not expensive, relatively maintenance free and easy to fit on the ring as you suggest. I don't have a copy of wiring regs, but I thought the recommendation was that immersion heaters and permanently connected heating appliances forming part of a comprehensive heating system should be on separate circuits and not connected to the ring. I thought the usual method of wiring storage heaters was on radial circuits which are each designed for a maximum load of 3.4kW both for current capacity and voltage drop. That means for most houses a 2.5mm² radial circuit, up to about 30m, would be ok. If each circuit is designed for the 3.4kW load then a 20A switch with flex cord outlet is needed and not a plug and socket. This allows for upgrading to the 3.4kW heater without any changes to the circuit. I've got a separate CU for my off-peak demands which is 8 storage heaters and an immersion element. I really think this is the way to wire this stuff but I'm only diy, and may have been wrong on my views of earthing metal capping for cables outside permitted zones, so I'm here to learn if I'm wrong. (I thought you were a pro plugwash?)

 

[brown-nought]

Personally I don't think plugs and storage heaters mix. Sockets don't like to be run at a full load for long periods. Rings aren't suitable to high constant loads either.

The best option is a radial circuit with short dp switched unfused flex spurs to the heaters. The heater is then fixed equiptment and only need 5s disconnection time rather than 0.4 with a socket.

Since circuits run near or at design load for long periods grouping factors must be considered during design/installation.

 

[ban-all-sheds]

The best option is a radial circuit with short dp switched unfused flex spurs to the heaters. The heater is then fixed equiptment and only need 5s disconnection time rather than 0.4 with a socket.

Indeed.

Still no word from malawihap on why when he installs these circuits he won't be able to put the outlets close enough to his storage heaters that their flexes will reach....

 

[AdamW]

Still no word from malawihap

Possibly he had one of those "oooooh c**p" moments, where he realised that this was going to be a lot more work than he had hoped.

 

[malawihap]

lol i opened up a can of worms here didn't i , all i wanted to know was where to buy the cable but thanks for the input guys.

 

[ban-all-sheds]

Was that all you wanted to know because you thought that was all you needed to know?

Were you planning to plug them into a ring main?