Pendant and shade not suitable for bathrooms?

[stillp]

Perhaps you are. So why are you misrepresenting my view?

 

[JohnW2]

No, of course I don't. Also bear in mind that most RCD operations are not caused by current flowing through a person to earth but by current flowing through a fault to earth, so some lives will be saved by avoidance of some fires.

True - although, other than in TT installations, ADS ought to prevent such fires - so the only fires prevented (in TN installations) would be those due to (pretty rare) deficient ADS, and even most of those fires would not have resulted in deaths.

Kind Regards, John

 

[stillp]

ADS ought to prevent such fires

Yes it ought - in correctly designed and installed installations.

 

[JohnW2]

Perhaps you are. So why are you misrepresenting my view?

Maybe I'm somewhat misrepresenting your view as expressed in this thread (in which yiu did include the "unless..." qualification) - in which case I apologise. However, more generally you commonly make similar statements without any such qualification. Indeed, earlier today, in another thread, in response to my comment about a risk which I said was "already incredibly small", you wrote:

So because a risk is small, you are suggesting there is no need to reduce it further?

... without any qualification.

Kind Regards, John

 

[JohnW2]

Yes it ought - in correctly designed and installed installations.

Exactly, and since the Standard already requires that the installation be correctly designed and installed in that respect (ADS), is necessarily reasonable add a further regulation in case designers/installers choose to ignore or contravene the first one?

Kind Regards, John

 

[stillp]

in which case I apologise

Apology accepted, thank you.

... without any qualification.

That is correct, but in that post I was asking you to clarify your position, not stating my opinion.

 

[JohnW2]

That is correct, but in that post I was asking you to clarify your position, not stating my opinion.

OK - but, particularly given the emoticon you added after the question mark, I took it as an essentially rhetorical question, implying that you felt that efforts should be made to reduce the risk further, even if it were "already incredibly small". Sorry if I misunderstood your intention, and emoticon.

Kind Regards, John

 

[Glastoun]

Looking at the regs, they are to do with jets of water potentially hitting the fitting, not people touching them with wet hands. The highest spec lights are those that can be submerged underwater like for a jacuzzi. Anyway, the fitting isn't separate from the glass shade so it'll have to go back.

 

[Adam_151]

I think there does exist a number of potential faults which have the potential to result in a fire, but would not be disconnected by correctly installed ADS until its possibly too late (but might well be disconnected by an RCD far quicker). The regs do recognise this but only call for RCD protection when the surroundings are pretty combustable (such as woodworking machine shops).

Generally such faults will consist of failures of would components (such as a lamp choke, for example) where the winding has got hot, the enamelling has burnt off, the turns have shorted, current has increased, its got hotter still. After a while it'll fault to the core, but depending on where in the winding this is, it might be insufficent to operate ADS, and instead just serve to increase teh current further. Sooner or later it will fail in such a way that the current stops (either a fault involving earth at the supply end of the winding that takes the circuit out... or as I've know happen, a sizeable chunk of the windings shorted out of circuit while the lamp is lit... which removes the lamp from cirucit by exploding it!) but it will run very hot for a good while first and make a bad smell, most of them come to no harm, but sometimes things get hot enough that a fire alarm activation happens and the fire brigade gets called.

I've seen heating pumps that have tripped an RCD out due to low IR, upon bypassing the RCD and running the pump (while supervised), it got very hot and started smoking. Now that heating system didn't have to be on RCD and the pump was located in an airing cupboard full of laundry... what would have happened if there wasn't an RCD to trip in the first place?

 

[JohnW2]

I think there does exist a number of potential faults which have the potential to result in a fire, but would not be disconnected by correctly installed ADS until its possibly too late (but might well be disconnected by an RCD far quicker). .... Generally such faults will consist of failures of would components (such as a lamp choke, for example) where the winding has got hot, the enamelling has burnt off, the turns have shorted, current has increased, its got hotter still. After a while ....

Overload of equipment (as opposed to a negligible impedance 'fault') is not dealt with by 'ADS' and may well not be dealt with by any OPD. The OPD is there primarily to protect the cables, and may well 'legitimately' allow enough current to flow (maybe 'indefinitely') to create a fire risk in a (faulty) connected load. If that is a potential scenario (i.e. if the equipment may present a fire risk at a level of overload current that is within the legitimate current-supplying capacity of the circuit), then the equipment in question should have its own internal over-current protection.

An RCD will obviously not operate in response to an ("L-N") overload, per se, so it would only be helpful in the sort of situation you describe if there were an L-E or L-N fault as well as the ("L-N") overload. That may happen, but is very far from guaranteed.

Kind Regards, John