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Discuss RCD's and storage heaters in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

R

rasell

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Are there any known issues with RCD's and storage heaters?

I've done an inspection on my own house, the storage heaters are on their own board, its a TNCS system. The only problem is that when they were installed the wires were tucked under the joists rather than through a hole in the middle. So I did not think they had adequate mechanical protection.
However as the electicity only comes on in the night its unlikely that someone would be drilling holes then.
How do people do an installation cert. when there is no power? I can't imagine people coming back in the middle of the night!

I was thinking of protecting the board with a 30mA RCD to meet the regs and for extra safety. Are there any likely problems with nuisance tripping?

Regards

Marc
 
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R

randyrat

  • Thread Starter Thread Starter
  • #2
Nothing wrong with the install provided it met the regs when fitted...my house is all chiseled joists, as is every other house in this estate that was built at the same time. Just because this doesnt meet current regs doesnt mean its wrong. It should be marked as a "4" on the PIR. For your own peace of mind you could fit RCD protection, as this deficiency is also a "4" on the PIR if you don't have an RCD board. Nuisance trips are usually the fridge or fridge/freezer, and it is common practice to run the supply to this without RCD to prevent such trips.
 
R

rasell

  • Thread Starter Thread Starter
  • #3
Nothing wrong with the install provided it met the regs when fitted...my house is all chiseled joists, as is every other house in this estate that was built at the same time. Just because this doesnt meet current regs doesnt mean its wrong. It should be marked as a "4" on the PIR. For your own peace of mind you could fit RCD protection, as this deficiency is also a "4" on the PIR if you don't have an RCD board. Nuisance trips are usually the fridge or fridge/freezer, and it is common practice to run the supply to this without RCD to prevent such trips.
Thanks for the reply, when did it become a requirement to have mechanical protection?
Even if its not required I like to have things as safe as possible in my house.

I forget to mention that the meter tails are 16mm2 so I'm assuming I will have to upgrade them to 25mm2.

Regards

Marc
 
R

randyrat

  • Thread Starter Thread Starter
  • #4
Meter tails are the responsibility of the electricity supplier...If you want them changed you'll have to contact them direct. The consumer tails (i.e from the Suppliers Isolation to your CU) are yours, yet there is little point in upgrading them if the supply is insufficient. Check with your supplier first
 
S

Stixicus

  • Thread Starter Thread Starter
  • #5
That's an interesting question - how do people do an installation cert for a board and or circuit when there is no power there at the time due to it being supplied by "off peak" energy, I have tested storage heaters to find a fault by temporarily connecting the circuit to a spare way in the "normal" board for the property with chocblock and an extra piece of t+e to extend it - this is the only way I can think of to produce "live" test readings such as Zs and RCD testing (if RCD protected off peak board).....without coming back in the middle of the night.
 
J

JulesHurley

  • Thread Starter Thread Starter
  • #6
As Stixcus has said, when testing Eco 7 boards, or fault finding, I normally jump across boards.
 
I

ian hall

  • Thread Starter Thread Starter
  • #7
Fitting an rcd to storage heaters seems alien to me. I looked at a board change today and figure that to comply i will need to rcd the heaters.
 
R

randyrat

  • Thread Starter Thread Starter
  • #8
According to regs, you are allowed to have an item supplied independent of an RCD provided it is socket fed and specifically labelled for that item of equipment. (reg 411.3.3 if you're interested)
As night storage heaters are not usually socket fed, but are "fixed equipment" I am pretty sure the regs about RCD protection do not apply.
Anyone got any other ideas???
 
J

JulesHurley

  • Thread Starter Thread Starter
  • #9
The only reason I can see to RCD heaters, would the depth of cables etc, same reason as smoke alarms.
 
I

ian hall

  • Thread Starter Thread Starter
  • #10
The job in question has the cables buried in the plaster, so theroretically it needs rcding??

Ian
 
That's an interesting question - how do people do an installation cert for a board and or circuit when there is no power there at the time due to it being supplied by "off peak" energy, I have tested storage heaters to find a fault by temporarily connecting the circuit to a spare way in the "normal" board for the property with chocblock and an extra piece of t+e to extend it - this is the only way I can think of to produce "live" test readings such as Zs and RCD testing (if RCD protected off peak board).....without coming back in the middle of the night.
older type have a small slider switch in the teleswitch,which you can flick to give you power at any time but I think you might have to break the seal to get at it. oh no!
 
I

ian hall

  • Thread Starter Thread Starter
  • #12
I,ve had a few faulty rcd,s recently so testing that without power would be a prob. Would make sense to link out to perm live side i suppose.

This job just gets more complicated don,t you think. Would never have thoght we would be rcd,ing storage heaters, cookers ,lighting and immersion heaters (assuming they are flush wired)

So many things seem open to interpretation. I will have a few questions when my Niceic inspection comes up soon.

Ian
 
L

lister

  • Thread Starter Thread Starter
  • #13
I've never seen a seal on a teleswitch yet:D:D:D:D:D
 
R

randyrat

  • Thread Starter Thread Starter
  • #14
You only need to RCD the heaters if it is a new install. There is no requirement in 17th ed to upgrade an existing install to provide an RCD, unless you want to that is. A CU upgrade will require an RCD in this case, as you state the cables are shallow and unprotected, and as such require the additional protection.
(See OSG 3.6.1)
 
I

ian hall

  • Thread Starter Thread Starter
  • #15
It is a small studio flat, has 5 on peak circuits and 2 off peak. I am going to try and get it all in 1 enclosure.
Way i see it, i will have a main switch isolating 2 rcd,s and 5 mcb,s then another rcd isolating 2 mcb,s for the off peak. What a lot of switches to explain!!

Ian
 
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