Security light on FCU, is this really necessary?

[JohnW2]

it may be a single pole switched FCU ….

I'm not convinced that they ever existed, but they certainly haven't in recent decades,

 

[JohnW2]

So what would that mean for me then?

Don't worry - it won't be single-pole

 

[SUNRAY]

I don't really understand. How does anything else make much sense of the fact that he wrote:

... and then 6 minutes later wrote ....

... are you perhaps suggesting that his second post was intended as a 'retraction' of the first one (i.e. he was meaning something like "however, having thought properly about it, and given the FCU is.a DP isolator - why bother...?" ??

You're reading it all out of context or sequence, I agree he seems to be saying funny things but the comments are responses. Read the whole lot and it does make sense.

 

[IfInDoubtDIY]

I realised that earlier @Murdochcat asked if I was 100% certain that this FCU was not connected to the socket circuit. I actually wasn’t 100% certain as I’d always remembered it being connected to the lighting circuit (since moving into the house in 2023). So I just went out to the garage, flicked on the FCU, and the neon lit up. I flicked the SOCKETS MCB to OFF and the neon stayed on. I flicked the SOCKETS MCB back ON and then flicked the LIGHTS MCB to OFF, and the neon light went out.

I know a few professional sparkys on here will insist that doesn’t prove anything, but as far as I am concerned the FCU is connected to the lighting circuit.

 

[JohnW2]

I know a few professional sparkys on here will insist that doesn’t prove anything, but as far as I am concerned the FCU is connected to the lighting circuit.

On the basis of what you have described, I would hope that no-one, professional electricians or not, would disagree with your interpretation

 

[JohnW2]

You're reading it all out of context or sequence, I agree he seems to be saying funny things but the comments are responses. Read the whole lot and it does make sense.

I still don't get your point. The relevant 'whole lot of it' is simply three consecutive posts, two being ..

I would suggest you replace the FCU with a DP isolator....

... and then 6 minutes later ....

But given the FCU is.a DP isolator - why bother at all?

... the only post in-between them being ...

That’s my thinking.

What aspect of "context or sequence" do you believe I am mis-reading or missing?

 

[SUNRAY]

I’m wondering if it could be replaced with just a regular switch).

Any thoughts?

I would suggest you replace the FCU with a DP isolator, not just a standard light switch

But given the FCU is.a DP isolator - why bother at all?

I know there are other post but I simply can't read that any other way.

 

[JohnW2]

I know there are other post but I simply can't read that any other way.

Nor can I - which is why I am confused by you're repeated insistence that I 'mis-read' something...

.... if (because an FCU invariably includes a DP switch) he very sensibly wrote "why bother at all" (to change FCU to DP isolator), then why, 6 minutes earlier did he write "I would suggest you replace the FCU with a DP isolator" ??

 

[IfInDoubtDIY]

I think we should all stop this discussion now as we’re getting nowhere. My question has been answered I COULD replace the FCU with an isolator switch, but it may not be necessary to do so. End of story.

 

[EFLImpudence]

I COULD replace the FCU with an isolator switch, but it may not be necessary to do so. End of story.

The FCU is an isolator switch.

 

[IfInDoubtDIY]

The FCU is an isolator switch.

I know that!!

 

[SUNRAY]

post removed

 

[SUNRAY]

I think we should all stop this discussion now as we’re getting nowhere. My question has been answered I COULD replace the FCU with an isolator switch, but it may not be necessary to do so. End of story.

Indeed, I'd keep it in circuit.

 

[IfInDoubtDIY]

Indeed, I'd keep it in circuit.

Thanks SUNRAY. I’ll replace if and when it fails, otherwise I’ll focus on just sorting out replacement of the light itself.

 

[JohnW2]

I think we should all stop this discussion now as we’re getting nowhere.

So it seems. I asked a simple question and am rather baffled by what is being thrown at me!

I COULD replace the FCU with an isolator switch, but it may not be necessary to do so. End of story.

Certainly not necessary. You would be replacing a DP switch+fuse with a DP switch without a fuse, and the fuse is doing no harm - so it would just be a waste of time, effort and money.

You seem to have convincingly established that the FCU is fed from the lighting circuit. Had that not been the case (i.e. if it had been fed from the sockets/power circuit) then that would have been a reason NOT to replace the FCU with a switch, since the fuse in the FCU would when have been serving a desirable function.