After good RCBO consumer unit

[driverman]

Hi guys, I'm looking for a good easy to install 1 Phase domestic 20 + way RCBO consumer unit (possibly flush) Several large cables to be installed including a 16mmm SWA.
I'm fitting RCBO's to all circuits. Any recommendations. I've not had much time to browse on the internet but I seem to get lost on there with the various products. Thanks

 

[davesparks]

SBS trade sales sell a variety of different CUs and all with SPSN RCBOs

 

[telectrix]

with a 16mm SWA involved, i'd go for a metal case CU.

 

[driverman]

with a 16mm SWA involved, i'd go for a metal case CU.

Yes I agree re metal case....was thinking of going flush..........no IP rating to worry about then, with all the various cables entering the unit. When surface do most electricians now use trunking or similar?

 

[Pete999]

How do you intend to terminate the SWA into a Domestic CU? I would go for a Metal clad CU

 

[davesparks]

It still needs to have the appropriate IP rating if it is flush mounted!

If it's a new build job then chase an adaptable box in behind the CU position to bring all the cables in to at first fix stage. Then the plasterers can get a decent flat finish a lot easier than with a big bunch of cables sticking out.

 

[telectrix]

what. be nice to spreads. ? sod off with that.

 

[driverman]

How do you intend to terminate the SWA into a Domestic CU? I would go for a Metal clad CU

I was thinking of a flush metal consumer unit..........take all the guts out........chop into wall, luckily only term/blocks. Terminate the SWA cable and coil up with the other pvc cables with in the box.

 

[driverman]

It still needs to have the appropriate IP rating if it is flush mounted!

If it's a new build job then chase an adaptable box in behind the CU position to bring all the cables in to at first fix stage. Then the plasterers can get a decent flat finish a lot easier than with a big bunch of cables sticking out.

Re IP rating, what I meant was, if all the cables entering the the top of flush unit are then plastered over then no gaps for the 1mm stiff wire test. Where as, if surface mounted and grommets used, possibly IP rating not so good.

 

[Pete999]

I was thinking of a flush metal consumer unit..........take all the guts out........chop into wall, luckily only term/blocks. Terminate the SWA cable and coil up with the other pvc cables with in the box.

But surely if you are going to chop a metal box in behind the CU and terminate the SWA and then plaster over, what happens when you come to test and find the gland is/has become loose and the chemical reaction between the brass element of the gland and the plaster degrades and causes failure of the termination, your method, although would make a neat installation, the gland connection is not maintenance free, if you get what I mean. Keep it surface mounted and run the cores and a cpc connected to the gland via a banjo into the CU, access to all joints is achieved there will be no IP issues as you would, I assume, either mount the CU and the adaptable box in such a way that there would be no gaps, by using a Male and Female brass bush of the correct size.

 

[telectrix]

good point dave ( sorry, pete ) . looks like the dementia pills are working today . :wheelchair: hehe,

 

[driverman]

But surely if you are going to chop a metal box in behind the CU and terminate the SWA and then plaster over, what happens when you come to test and find the gland is/has become loose and the chemical reaction between the brass element of the gland and the plaster degrades and causes failure of the termination, your method, although would make a neat installation, the gland connection is not maintenance free, if you get what I mean. Keep it surface mounted and run the cores and a cpc connected to the gland via a banjo into the CU, access to all joints is achieved there will be no IP issues as you would, I assume, either mount the CU and the adaptable box in such a way that there would be no gaps, by using a Male and Female brass bush of the correct size.

Not that I'm into this a lot, but I was under the impression 1 end of the SWA cable could be buried but not both ends. One end must be exposed as you say for testing. In this case it will be, as other end will be in the detached garage. Now you have got me thinking with what you have said. Is what I said OK to comply using 2 X core SWA or do I have to use 3 core SWA using the third core as an earth?

 

[Andrewr3]

But surely if you are going to chop a metal box in behind the CU and terminate the SWA and then plaster over, what happens when you come to test and find the gland is/has become loose and the chemical reaction between the brass element of the gland and the plaster degrades and causes failure of the termination, your method, although would make a neat installation, the gland connection is not maintenance free, if you get what I mean.

What he said. I had a job recently where a SWA was connected into the back of a plastered and cut into wall metal box where the gland connection needed attention! What pain for access as the gland was buried in the wall as well! It looked as if damp was the cause of the problem as well. This was just one SWA, imagine if I had to take off another two or three SWA's in the same box just to get access to one gland.

 

[Pete999]

good point dave ( sorry, pete ) . looks like the dementia pills are working today . :wheelchair: hehe,

Thanks Pete, oh no thats me

 

[driverman]

Thanks Pete, oh no thats me

Do many installations have buried SWA installations? Is it allowed by BS7671? Don't get me wrong I fully understand your point of view. No point making life difficult for myself or indeed another electrician further down the line. Just like to get an overall picture of what is allowed not allowed and practicable. thanks