Can any one identify this please?

[Iggifer]

I think many people probably would agree with you and your boss - but where does one stop, and how sensible is it? ....

... is there, for example, really much material difference between a 60A or 80A switch-fuse and an 50A shower or cooker isolator/switch (or do you perhaps think that they get caught by Amd3 as well?!)

Kind Regards, John

Nope I wouldn't say you'd need one for a shower/cooker isolator but I see your point.

I'd draw the line at Consumer Units and Switch Fuses. And MAYBE if I was being anal, I'd want adaptable boxes that're used to extend cables in a CU move to be metal ones. Thankfully haven't had to do one like that since Amd3 so haven't had to decide.

But then, whats the difference between 10 circuits joined in an adaptable box to 10 circuits in a DB? The tails?

Metal switch fuses have become stocked more at wholesalers over the past few months, when we started asking for them, we had to go to CEF and we had one choice, now we can go into any of our wholesalers and choose from 2 or 3. That being said, if you don't specify metal you'll get a KMF, so plenty of people must still be fitting them

 

[JohnW2]

Nope I wouldn't say you'd need one for a shower/cooker isolator but I see your point.

I don't think many people would - but what is it that makes the switch-fuse, but not the isolator, "switchgear"? ... and, of course, an FCU is merely a type of (relatively low current) "switch-fuse"!

And MAYBE if I was being anal, I'd want adaptable boxes that're used to extend cables in a CU move to be metal ones. Thankfully haven't had to do one like that since Amd3 so haven't had to decide. ... But then, whats the difference between 10 circuits joined in an adaptable box to 10 circuits in a DB? The tails?

Quite. Well, I suppose the difference is that "switchgear" probably requires some sort of switch, rather than just a 'joint'? ... and I'm not sure that the number of circuits is an issue, given that the switch-fuse you feel is caught by Amd3 only have "one circuit" in it - so the hypothetical argument you've presented could presumably be applied to any JB, particularly, say, a 60A one?

Kind Regards, John

 

[Iggifer]

I don't think many people would - but what is it that makes the switch-fuse, but not the isolator, "switchgear"? ... and, of course, an FCU is merely a type of (relatively low current) "switch-fuse"!
Quite. Well, I suppose the difference is that "switchgear" probably requires some sort of switch, rather than just a 'joint'? ... and I'm not sure that the number of circuits is an issue, given that the switch-fuse you feel is caught by Amd3 only have "one circuit" in it - so the hypothetical argument you've presented could presumably be applied to any JB, particularly, say, a 60A one?

Kind Regards, John

Well this is the problem of this regulation isn't it? The IET say it's to reduce fires in consumer units, and the issue is loose connections. If there's a plastic adaptable box with 29 tight connections and one loose one, and a metal CU with 30+ tight connections, we all know where the fire is going to start.

Yes, the box is upstream of the OPD, but does that realistically make a difference?

You could hypothetically apply it to any JB or indeed accessory using that logic, but then I personally have seen many, many more heat damaged accessories than I have MCBs.

Is the point that you can't isolate a burning consumer unit but once the JB has burst into flames you can at least kill the power?

 

[EFLImpudence]

No. The point is the regulation was brought in to appease the London Fire Brigade and is ill-conceived.

 

[Iggifer]

Well, yea. I wholly concur with that statement

 

[JohnW2]

Well this is the problem of this regulation isn't it?

Quite so!

The IET say it's to reduce fires in consumer units ...

Not even that. The amendment to the regs does nothing to reduce (the cause of) such fires - merely an attempt to reduce the spread of fire once it has started in a CU!

Is the point that you can't isolate a burning consumer unit but once the JB has burst into flames you can at least kill the power?

I doubt that the LFB even thought of that - if that had been their reason, they would logically have merely asked for isolators (metal enclosed?!) to be required upstream of plastic CUs!

Kind Regards, John