RCBO 's

[jaguar1]

I assume that you have to fit a double pole rcbo at the consumer unit to protect your sockets as they may be used outside in the garden , ie in the event of a fault both the live and neutral are isolated , would you be allowed to fit a single pole rcbo for sockets ??

 

[Taylortwocities]

Most RCBOs only break the phase and occupy a single space in the consumer unit (to replace an MCB, for example).

Generally, RCDs are double pole and disconnect both phase and neutral.

The answer to your general question is, generally, yes.

 

[jaguar1]

I am trying to understand what difference does it make if you only cut the live conductor (if you used a single pole rcbo) as the live would be dead in the event of a earth fault and the danger should be gone . Why is it any safer if the neutral is cut as well ???

 

[RF Lighting]

It removes and danger associated with reversed polarity wiring, and also removes any chance of a dangerous potential existing between earth and neutral, although this is very unusual.

 

[jaguar1]

Thanks for your reply RF the cross polarity makes perfect sense !!

 

[Spark123]

But as an RCBO is at the consumer unit, the risk of a professionally installed having reverse polarity is minimal.

 

[jaguar1]

spark 123 ,

I assume you meant if it was a single pole rcbo at the consumer unit - i still thought it had to be double pole to satisfy the 17th ??

 

[ban-all-sheds]

AFAIK the 17th doesn't introduce any extra requirements for DP devices in CUs...

 

[jaguar1]

So still confused -i am thinking it has to be a double pole rcbo to protect the garage supply cable as with sockets in the house the rcd will switch off both the live and neutral at the same time .

 

[ban-all-sheds]

What garage supply cable? You were talking about sockets:

I assume that you have to fit a double pole rcbo at the consumer unit to protect your sockets as they may be used outside in the garden , ie in the event of a fault both the live and neutral are isolated , would you be allowed to fit a single pole rcbo for sockets ??

Tell us more about the garage supply cable, and why you think it needs RCD protection.

 

[Adam_151]

AFAIK, no need for double pole RCBOS

There is a requirement for RCDs to interupt all line conductors, you can easily see that as something else if you are skim reading quickly...

 

[jaguar1]

Sorry , i was thinking about a garage supply cable at the time as i was trying to make the relation with outdoor circuits ie the sockets could be used outside.

So could i use a single pole rcbo to protect my garage supply cable or does it have to be a double pole rcbo ??

 

[industryspark]

Jaguar1 wrote

So could i use a single pole rcbo to protect my garage supply cable or does it have to be a double pole rcbo ??

you dont need rcd/rcbo protection of a gararge supply cable generally, unless we are going into issues brought up by the upcoming 17th edition and even then it depends on the cable run/installation method.

why not a normal mcb for a dedicated garage CU housing rcbo for the sockets and mcb for the lights, or a common rcd.

what you use depends on other factors of course.

 

[jaguar1]

I thought anything outside the house that is electrical ie cable should be protected by a rccd , what if the garage supply cable whic is a 6.00mm twin & earth protected by plastic conduit was damaged and it was'nt protected by a rcc back at the house.

 

[securespark]

Post deleted.

Apologies for my misleading advice.

I did not have a copy of the regs with me and I misinterpreted some scribbled notes I had made on my 17th update course.