Switched fuse spur

[securespark]

Forget the spur.

Run some 1 milli back to the board, whack it on a 16A breaker and have done with it.

 

[plugwash]

You can get BS1362 fuses down to 1A if you want though 3A or 5A is fine for this kind of thing*

*even 13A may be depending on the type of light fitting and the intallation mechanisms of the cable

 

[ban-all-sheds]

I was always taught to use the smallest fuse

Who taught you that, and did their explanation indicate that they knew what the fuse was for?

 

[riveralt]

I was always taught to use the smallest fuse

Who taught you that, and did their explanation indicate that they knew what the fuse was for?

Thank goodness it wasn't the same supercilious person who was giving advice like this

You need to wrap them in aluminium foil to make them bigger.

 

[ban-all-sheds]

Sense of humour failure, riveralt?

 

[The Dentist]

One other thing everyone forgot to mention is to make sure that any exposed cable has adequate protection for its environment

I have seen many pubs and clubs with T&E (usually painted over) clipped to walls ceilings and skirting boards next to dardboards, although I guess this could be natures way of removing bad players from the gene pool

 

[plugwash]

though I wonder could burried cables be even worse? at least with the cable on the surface you can see when a dart has hit it and get someone to turn off the power before trying to pull it out.

 

[JohnW2]

I was always taught to use the smallest fuse

Who taught you that, and did their explanation indicate that they knew what the fuse was for?

Even if one believes, as your question implies you do, that the fuse exists only to protect the cable, it still makes sense to use the smallest possible fuse, since that will optimise protection and minimise disconnection times in the case of an overload or fault. If one believes that the fuse has a useful function in protecting everything downstream of the fuse, then the argument becomes stronger. Put the other way around, what is the perceived advantage of using a fuse of higher rating than is necessary for the load in question?

Kind Regards, John.

 

[EFLImpudence]

Small enough to afford the required protection isn't higher than necessary.

 

[JohnW2]

Small enough to afford the required protection isn't higher than necessary.

I said 'higher than necessary for the load in question' and a fuse small enough to provided the ('minimum') required protection surely can qualify as that?

Kind Regards, John.

 

[EFLImpudence]

I said 'higher than necessary for the load in question' and a fuse small enough to provide the ('minimum') required protection surely can qualify as that?

Ok.

The fuse isn't there for the load (apart from dubious MIs).
From what would it protect the load? 10mm² cable, 50A MCB, - 40W lamp or 10kW shower.

It's there for the cable.

 

[TicklyT]

One other thing everyone forgot to mention is to make sure that any exposed cable has adequate protection for its environment

I have seen many pubs and clubs with T&E (usually painted over) clipped to walls ceilings and skirting boards next to dardboards, although I guess this could be natures way of removing bad players from the gene pool

So that's why there's a rubber mat under the dartboard!

 

[JohnW2]

Ok. The fuse isn't there for the load (apart from dubious MIs). From what would it protect the load? 10mm² cable, 50A MCB, - 40W lamp or 10kW shower. It's there for the cable.

Yes, we both know that the regs are only interested in OPDs in terms of cable protection, and that they are satisfied so long as the OPD is rated appropriately in relation to the tabulated maximum CCC of the cable - so I suppose it's likely that many electricians are content to just comply with that.

However, that doesn't mean that some 'protection' over and above the minimum required by the regs (e.g. protection of what's on the end of the cable) cannot be achieved by using an OPD (e.g. fuse) of lower rating than that which would be required to satisfy the regs.

Kind Regards, John.

 

[ban-all-sheds]

But how does that morph into "I was always taught to use the smallest fuse"?

That implies consistent teaching over a significant time by more than one teacher.

 

[JohnW2]

But how does that morph into "I was always taught to use the smallest fuse"?

You'd have to ask riveralt that. I'm merely pointing out that, in the minds of those who are interested in 'protection' over and above the minimum required by BS7671, it wouldn't be unreasonable teaching.

Kind Regards, John.