2 circuits on 1 mcb

[Lurch]

So long it follows the same route and of equal loading

What is?

 

[kme]

So long it follows the same route and of equal loadingJohn

EH????

What follows the same route? And, same route as what?

I don`t understand your post there, mate. Come to that, what is the bit about "equal loading"? The two rings? Doesn`t matter!

You could put your sockets & pendants on the same breaker if you want - the only caveat being:

1. you use a protective device low enough to protect the lighting cable.

2. you wire the whole lighting circuit in 2.5mm, with 20A wall switches, and a 16 or 20 A protective device

(alright, you`d be crackers to do either; but they`d comply........)

 

[Lurch]

There's the rest of this thread in my inbox. With BangBangs permission I'll stick it here so it finishes off the odd loose end.

BangBang, may I?

 

[BangBang]

Go Ahead Lurch

 

[Lurch]

Snipped a couple of irrelevant bits....

Sorry Cables of equal size and follow the same routecan be fed off the Fuse/MCB

I see. You're wrong anyway. If you're doubling up cbales to feed the same device they should be the same size and follow the same route. If they are in the same MCB they can be whatever they want as long as they are within the CPD and circuit limits.

What would you put down for R1+R2

Measure all R1+R2's and write down the highest. You'd have to do the same with your way anyway.

Over the weekend I'll dig out the regs book and send the numbers over

 

[kme]

Ah. Thanks both

 

[PBC_1966]

You could put your sockets & pendants on the same breaker if you want - the only caveat being:1. you use a protective device low enough to protect the lighting cable.

2. you wire the whole lighting circuit in 2.5mm, with 20A wall switches, and a 16 or 20 A protective device

(alright, you`d be crackers to do either; but they`d comply........)

Subject to installation method, grouping, and voltage drop, 1.5 sq. mm could be adequate on a 16A circuit. Mixed lighting/socket circuits wired in 1.5 on a 16A MCB are common on the Continent.

And similarly mixed circuits wired in 14 AWG (equivalent to just over 2 sq. mm) on 15A or 12 AWG (3.3 sq mm) on 20A circuits are the norm in North America.

 

[kme]

I`d also have thought that max. Zs could limit the length of the cct quite considerably!

 

[Risteard]

It wouldn't be two circuits on one MCB by virtue of the fact that they are protected by the same MCB. This, by definition, makes it one circuit.

 

[Apache]

It wouldn't be two circuits on one MCB by virtue of the fact that they are protected by the same MCB. This, by definition, makes it one circuit.

Applaud Smiley

 

[kme]

Risteard: see Lurchio. Page 1, post 2

 

[Lurch]

It wouldn't be two circuits on one MCB by virtue of the fact that they are protected by the same MCB. This, by definition, makes it one circuit.

That's exactly what I said at the start.

 

[Andy™]

I see. You're wrong anyway. If you're doubling up cbales to feed the same device they should be the same size and follow the same route. If they are in the same MCB they can be whatever they want as long as they are within the CPD and circuit limits.

wrong. conductors in parallel do not have to be same CSA. 433.4.2, also appendix 10

 

[Lurch]

Well as ever, specifically vague regs really!

I was informed of this verbally years ago, Not too sure where my older copies of BS7671 are, possibly something else that has changed slightly over the last 4 or 5 revisions. More likely it was told to me as a best practice method.

 

[Risteard]

Risteard: see Lurchio. Page 1, post 2

Oops... I missed that!