Wiring for induction hob

[JohnW2]

How about on a 40A shower circuit? My shower manual states to have accessable DP isolation, but like you say the CU main switch would provide that.

That's a 'requirement' that the manufacturer is attempting to impose. There is no regulation which requires it.

However, again, although isolation can be achieved at the CU, and given that showers are commonly quite a distance from the CU, there's something to be said for having something close to the shower which can be used as an 'emergency switch' (although I would think that it's probably extremely unlikley that such would ever be needed).

Kind Regards, John

 

[winston1]

Remember manufacturers instructions are a guidance only. They don't have to be followed especially when they are wrong, which is not infrequent.

 

[JohnW2]

Remember manufacturers instructions are a guidance only. They don't have to be followed especially when they are wrong, which is not infrequent.

Quite so.

In relation to the issue of showers that was raised, we hear far more about problems (some of which theoretically could result in fires) with shower isolators than with showers themselves.

Kind Regards, John

 

[winston1]

Partly because people insist on switching the isolators off after every shower.

 

[muffking]

Good info gents. I'll be leaving my isolator on then

 

[Seb101]

Good info gents. I'll be leaving my isolator on then

Indeed - I leave it on all the time, I consider it to be an emergency measure, though how it could possibly be manually operated to resolve a dangerous situation any faster/safer than the RCD on the circuit, I have no idea.

However it clearly states in my shower user/installation manual that the shower should have an isolator, and the isolator should be switched on and off before and after every shower. A typical case of appliance manufacturers enforcing what they consider to be 'safety' requirement, but actually creating the possibility for even more dangerous situations. Also trying to wire 10mm2 cable into a 45A ceiling isolator was a f*cking nightmare.

 

[winston1]

However it clearly states in my shower user/installation manual that the shower should have an isolator, and the isolator should be switched on and off before and after every shower. A typical case of appliance manufacturers enforcing what they consider to be 'safety' requirement, but actually creating the possibility for even more dangerous situations.

As I have said before manufacturers instructions are guidance only and don't have to be followed especially when they are wrong, which is not infrequent, as this example shows.

 

[Seb101]

As I have said before manufacturers instructions are guidance only and don't have to be followed especially when they are wrong, which is not infrequent, as this example shows.

I assume they do it to indemnify themselves from claims against electrical malfunction of the shower unit. If the shower malfunctions and opens the shower valve while you are out of the house, they will just say "it should have been isolated at the time as per the manual"

 

[winston1]

I assume they do it to indemnify themselves from claims against electrical malfunction of the shower unit. If the shower malfunctions and opens the shower valve while you are out of the house, they will just say "it should have been isolated at the time as per the manual"

Have you ever heard of that happening?

 

[Seb101]

Have you ever heard of that happening?

No - I'm just trying to find method in the madness.

 

[JohnW2]

Indeed - I leave it on all the time, I consider it to be an emergency measure, though how it could possibly be manually operated to resolve a dangerous situation any faster/safer than the RCD on the circuit, I have no idea.

As I said before, I totally agree. Intuitively, it sounds reasonable to have an 'emergency switch' close to the shower, but I struggle to think of situations in which it would be needed. Perhaps more reasonable with cookers/hobs etc. - but they are often postioned so that cannot be safely operated if the casing of the appliance becomes live or there are flames coming out of it.

However it clearly states in my shower user/installation manual that the shower should have an isolator, and the isolator should be switched on and off before and after every shower. A typical case of appliance manufacturers enforcing what they consider to be 'safety' requirement, but actually creating the possibility for even more dangerous situations.

Again as I said before, quite so!

Kind Regards, John

 

[JohnW2]

I assume they do it to indemnify themselves from claims against electrical malfunction of the shower unit. If the shower malfunctions and opens the shower valve while you are out of the house, they will just say "it should have been isolated at the time as per the manual"

That's quite possibly their thinking - but morally, if not also legally, one might feel that claims could be made against them if a house fire resulted from following their instructions to install an unnecessary isolator.

Kind Regards, John