RCD protection on immersion heater

[maltaron]

Prior to having solar panels fitted my consumer unit arrangement was as follows:
1. Main isolator
2 .RCBO for garden power
3. RCBO for lighting
4. RCBO for freezer circuit
5. Main RCD for remainder
6. Ring final 1
7. Ring final 2
8. Immersion heater
9. Shower
10. Spare

Now the electrician who wired the solar panels shifted the bus bars to leave 5 breakers to the left of the main RCD to free up the spare socket for the solar input (without RCD), but this also removed the RCD protection from the immersion heater. He told me that the immersion heater did not need an RCD. I am concerned about this, any comments would be appreciated. I could move the immersion heater to an RCD protected position as the electric shower has been replaced with a power shower off the ring final.

 

[EFLImpudence]

No appliances need RCD protection.

RCDs are for protecting people and in some instances, not yours, the wiring.

 

[JohnW2]

.... but this also removed the RCD protection from the immersion heater. He told me that the immersion heater did not need an RCD. I am concerned about this, any comments would be appreciated. I could move the immersion heater to an RCD protected position as the electric shower has been replaced with a power shower off the ring final.

As you've been told, the immersion heater does not need to have RCD protection (unless it's in a bathroom - and, even then, probably not if it were 'in a cupboard').

However, if you were concerned, in addition to what you've suggested (using the {no longer needed} RCD-protected 'shower way' for the immersion), you presumably could also change the MCB for the immersion to an RCBO, couldn't you?

Kind Regards, John

 

[Risteard]

I can't entirely agree that removing RCD protection where it already exists is a sensible (or generally defensible) course of action.

It is also likely that installation methods etc. did indeed create a requirement for RCD protection.

 

[JohnW2]

I can't entirely agree that removing RCD protection where it already exists is a sensible (or generally defensible) course of action.

One could say that but I think one would probably struggle to think of situations in which absence of RCD protection of an immersion heater circuit would result in an appreciable hazard.

It is also likely that installation methods etc. did indeed create a requirement for RCD protection.

I would think it even more likely that at the time the immersion circuit wiring was installed there were probably no requirements for RCD protection based on installation method - and regulations are, of course, not retrospective.

Kind Regards, John

 

[Risteard]

One could say that but I think one would probably struggle to think of situations in which absence of RCD protection of an immersion heater circuit would result in an appreciable hazard.
I would think it even more likely that at the time the immersion circuit wiring was installed there were probably no requirements for RCD protection based on installation method - and regulations are, of course, not retrospective.

Kind Regards, John

Irrelevant.

If it is required now for the installation method then you cannot justifiably remove it. When it was installed is completely and utterly irrelevant to that.

 

[EFLImpudence]

From what the OP writes, I do not understand why the immersion circuit was removed from the RCD coverage.

There was a spare way in the CU.

 

[DetlefSchmitz]

I am frequently puzzled why electricians seem to feed PV in through the consumer unit instead of into the/a henley block from the meter. There are major advantages to generation/usage monitoring if done that way. In particular (not in this case it seems) going into the CU seems to result in RCDs at both ends of the feed cable, which in my opinion cannot work in practice. I seem to remember that this was discussed at some length here some time ago.

 

[JohnW2]

From what the OP writes, I do not understand why the immersion circuit was removed from the RCD coverage. .... There was a spare way in the CU.

It is a bit confusing. It sounds as if it were not possible (or not 'convenient') to rearrange the busbars so that the RCD moved 'one place to the right), increasing the number of non-RCD slots from 3 to 4 (the RCD-protected ones then move 'one place to the right, and using the spare at #10), creating a non-RCD slot for the PV - but, instead, that the RCD 'had to be' moved two places to the right, increasing the number of non-RCD slots to 5, and meaning that one of the previously RCD-protected ones (the immersion circuit) therefore had to be shifted to one of the new non-RCD slots.

If I'm right in that speculation, then without seeing the inside of the CU, one can't tell whether it really was 'necessary' to do it the way they did!

Kind Regards, John

 

[JohnW2]

Irrelevant. If it is required now for the installation method then you cannot justifiably remove it. When it was installed is completely and utterly irrelevant to that.

I can understand that viewpoint, but I could also understand the contrary one - namely that the fact that a circuit was, for a period of time, 'unnecessarily' (in terms of regulations) RCD-protected does not mean that the 'unnecessary' RCD protection could not be removed.

In any event, you are merely guessing that the installation method of the immersion circuit cable is such as to require RCD protection, even now. Such circuits commonly go on the surface, through a ceiling & floor and into an airing cupboard, without being buried anywhere.

Kind Regards, John

 

[EFLImpudence]

It is a bit confusing. It sounds as if it were not possible (or not 'convenient') to rearrange the busbars so that the RCD moved 'one place to the right),

We don't know on which side the main switch is, but yes, right or left.

increasing the number of non-RCD slots from 3 to 4 (the RCD-protected ones then move 'one place to the right, and using the spare at #10),
creating a non-RCD slot for the PV - but, instead, that the RCD 'had to be' moved two places to the right, increasing the number of non-RCD slots to 5, and meaning that one of the previously RCD-protected ones (the immersion circuit) therefore had to be shifted to one of the new non-RCD slots.
If I'm right in that speculation, then without seeing the inside of the CU, one can't tell whether it really was 'necessary' to do it the way they did!

OR cut the busbar from no.10 way, fit MCB and supply with wire from main switch (or RCBO) and suitably label.

 

[JohnW2]

We don't know on which side the main switch is, but yes, right or left.

Well ...

... the electrician who wired the solar panels shifted the bus bars to leave 5 breakers to the left of the main RCD to free up the spare socket for the solar input (without RCD)

Since there were originally 3 non-RCD (RCBO) circuits and 5 (including 'spare') RCD ones, if the electrician changed things such that there are now 5 ways to the left of the RCD, the non-RCD ones must have been on the left (since, otherwise, he would not have changed anything!).

OR cut the busbar from no.10 way, fit MCB and supply with wire from main switch (or RCBO) and suitably label.

Yes, that would have been possible. As I said, if we knew what the inside of the CU looks like, there might also have been other 'easy' possibilities.

Kind Regards, John

 

[EFLImpudence]

Oh yes. Beg pardon re: left.