adding to a mcb

[Plonker 3]

A 13A spur will protect the cable and will leave no grey area so that's the way to go.

Why? The MCB is doing exactly the same job

Seeing as your taking a cable from the mcb anyway crimp one leg of the ring and extend the ring to the two sockets. Don't over think it, keep it simple

Again why as it is perfectly acceptable to put a 4mm radial on a 32 amp OCPD.

 

[Pete999]

Why? The MCB is doing exactly the same job



Again why as it is perfectly acceptable to put a 4mm radial on a 32 amp OCPD.

On the same cb as the RFC?

 

[Plonker 3]

Yes, why not?

 

[rich.250]

Perfectly fine in my opinion! Extending the RFC could be a nightmare.
Or as I've seen numerous times... Two Spurs off one point! In my opinion bad practice but most CB's can take 4x2.5 so it complies with regulations... :/

 

[garnhamr]

Seeing as your taking a cable from the mcb anyway crimp one leg of the ring and extend the ring to the two sockets. Don't over think it, keep it simple

+1
standard practice and most obvious as to whats happened later on meaning another sparky later on wont be, dare i say it 'ignorant' to the 4mm radial being fine and make a song and dance about it.

 

[Pete999]

Yes, why not?

Dillb, I am in disagreement with the issue of adding a 4mm radial to an already existing RFC, I can only quote app 15 as 1 un fused spur from any point on a RFC, there have been arguments for and against, its not something I would do,suffice to say imo I don't think it's the right way to go. Others will disagree with me, but thats OK we all have our opinions haven't we, end of as far as I'm concerned

 

[Deleted member 9648]

Dillb, I am in disagreement with the issue of adding a 4mm radial to an already existing RFC, I can only quote app 15 as 1 un fused spur from any point on a RFC, there have been arguments for and against, its not something I would do,suffice to say imo I don't think it's the right way to go. Others will disagree with me, but thats OK we all have our opinions haven't we, end of as far as I'm concerned

Just to correct you here Pete,app 15 does not state only one unfused spur from any point on a RFC,it states that an unfused spur can only supply one point.The two are not the same.

Edit....not wanting to get into a debate on the pro's and cons,just stating facts.

 

[Pete999]

Just to correct you here Pete,app 15 does not state only one unfused spur from any point on a RFC,it states that an unfused spur can only supply one point.The two are not the same.

Edit....not wanting to get into a debate on the pro's and cons,just stating facts.

Well OK then take your point, so are you saying tHat you can't take an un fused spur from any point on a RFC?

 

[telectrix]

you can take 2 unfused spurs from the same point on a RFC with the proviso that

1. you don't overload a short leg of the RFC, and

2/ each spur feeds only 1 outlet.

 

[Pete999]

you can take 2 unfused spurs from the same point on a RFC with the proviso that

1. you don't overload a short leg of the RFC, and

2/ each spur feeds only 1 outlet.

Show me where it states then Tel, and I'll shut up about it

 

[Geoffsd]

I can only quote app 15

What about 15B?

 

[Pete999]

What about 15B?

What about it?

 

[Deleted member 9648]

Well OK then take your point, so are you saying tHat you can't take an un fused spur from any point on a RFC?

No....not sure where that came from?

Show me where it states then Tel, and I'll shut up about it

The point is it doesnt say you can't

 

[Pete999]

No....not sure where that came from?



The point is it doesnt say you can't

So you're saying just because BS 7671 doesn't say you can't does that mean you can then?

 

[Plonker 3]

So you're saying just because BS 7671 doesn't say you can't does that mean you can then?

You know as well as most on here thats not true.

BUT as long as the the ccc of the cable is fine, Zs values comply, volt drop is acceptable then there is absolutely nothing wrong with a 4mm cable being used to spur several sockets on a RFC without the need for a FCU. All of these are highlighted in the BGB so there you go the regs does say it is acceptable.

 

[davesparks]

You can only have one point on an unfused spur.

The minimum cable size for a ring is 2.5mm, not the only permitted size.

So an unfused spur in 4mm is still an unfused spur and should only have one point connected to it for the ring circuit to comply with the standard ring circuit defined by the regs.

Of course you may choose to make a deviation from the regulations and install an unfused spur from the ring in 4mm with 2 points on it, and this would be perfectly safe if designed and installed properly but would still be a deviation.

 

[Pete999]

You know as well as most on here thats not true.

BUT as long as the the ccc of the cable is fine, Zs values comply, volt drop is acceptable then there is absolutely nothing wrong with a 4mm cable being used to spur several sockets on a RFC without the need for a FCU. All of these are highlighted in the BGB so there you go the regs does say it is acceptable.

Well why was the statement made, I don't mean to be difficult but the statement was made

 

[Octopus]

Just imagine what a newly qualified sparky would make of a 2.5 RFC and a 4mm radial in the same MCB!

 

[Pete999]

Just imagine what a newly qualified sparky would make of a 2.5 RFC and a 4mm radial in the same MCB!

Yep dead right Murdoch

 

[Silly Sausage]

Just imagine what a newly qualified sparky would make of a 2.5 RFC and a 4mm radial in the same MCB!

It'd give him something to think about and come to the conclusion that there's bugger all wrong with it!