Economy 7 CU

[jdmjrmdam]

Hi Folks, If a domestic installation that used Economy 7 and had a main CU and a separate CU for the storage heaters was being brought in line with the 17th edition. Would the "division of installation" rules that apply to the main circuits and dictate the use of a dual RCD board or RCBO's apply to the CU for the storage heaters? Or could this CU just have a singe double pole RCD as a main switch and MCB's for each heater circuit on the basis that it arguably wouldn't be hazardous or a major inconvenience if all the storage heaters were off in the event of a fault?

although it would be baltic in the morning!

 

[SPECIAL LOCATION]

Hi Folks, If a domestic installation that used Economy 7 and had a main CU and a separate CU for the storage heaters was being brought in line with the 17th edition. Would the "division of installation" rules that apply to the main circuits and dictate the use of a dual RCD board or RCBO's apply to the CU for the storage heaters? Or could this CU just have a singe double pole RCD as a main switch and MCB's for each heater circuit on the basis that it arguably wouldn't be hazardous or a major inconvenience if all the storage heaters were off in the event of a fault?although it would be baltic in the morning!

IMHO your assumptions of the actual hazard or risk of no storage heaters -vs- cost of RCBO's is a very sensible one!

One main RCD would most probs suffice,

and an emergency bag with the long thermal underwear! :^O ]

The other question to consider is?

How much of the storage heater wiring is buried in walls <50mm

IF it was just a very short bit up the wall to a D-Pole isolator, it may be sunk & placed in metal conduit OR surface.

and as there is NO socket outlet... NO need for RCD!

Guinness

 

[jdmjrmdam]

Thanks for the reply.

 

[PC Electrics]

I'd say it depends on how many storage heaters you've got. And how cheapskate the client is.

I've just done a bungalow which had just 3 storage heaters, so I put them on RCBOs - the customer didn't mind the small extra cost vs using an RCD main switch and didn't like the idea of one fault knocking out all the heating.

If you've got loads of heaters use a dual RCD board, then only half the heaters would be off in the event of a fault. Split the heaters up so that each RCD runs heating all around the house.

Or go halfway house and use a split loader with some heaters on the RCD and some on RCBOs.

skin..many..cat

 

[Andy™]

skin..many..cat

now thats just evil.

 

[Apache]

[quote name='Andy

 

[Evans Electric]

JD, why are you changing it all to the 17th in the first place. There is no requirement to go roound altering everything you come across. If it was done to the 16th what is the problem ?

Deke

 

[jdmjrmdam]

JD, why are you changing it all to the 17th in the first place. There is no requirement to go roound altering everything you come across. If it was done to the 16th what is the problem ?Deke

Just a theoretical question.

 

[NozSpark]

How about a single RCD CU and DP MCB's????

 

[jdmjrmdam]

How about a single RCD CU and DP MCB's????

Interesting. What would the double pole mcb's bring to the table if the RCD was double pole?

 

[NozSpark]

If the RCD were to trip you could fully isolate the circuits with a double pole MCB...

If you had a single pole MCB and a neutral fault then the RCD would still trip!!

It would at least let you have some heat until you managed to repair the faulty circuit.

 

[Apache]

Many people who have economy 7 and night storage heaters also use electricity to heat there water and the immersion shares the separate CU.

When water and electric mix i sleep sounder having it on an RCD. Which I have tested within the last month

 

[Andy™]

Which I have tested within the last month

is that test as in pressing the test button, or tested as in doing something wrong and the RCD saving you?!

 

[Apache]

[quote name='Andy