Rings or Radials ....

[Octopus]

Just started on a complete refurbishment / extension on a 3 bedroom property which is having a complete rewire.

I'm not keen on Dual RCD boards, nor trying to have as few circuits as possible ....

So when it comes to the socket circuits I was thinking of:

Radial 20A for hall, lounge and dining room
Ring 32A for kitchen
Radial 20A for upstairs

Anyone like to comment?


PS the plumber was asking me today why I was installing 35 mm boxes - he seemed to think 25 were always best!

 

[stevethesparks]

if you've got TT you can fit a full RCBO board and LEAVE the 100A DP switch upfront unchanged.

if you've got a dual RCCB board, that is when you need to change the upfront 100A DP to a 100mA type S.

Just belt and braces approach as was so cheap

 

[bigspark17]

In a dual RCCB board you have the brown and blue link leads between the main switch and the RCCB's and neutral bars IF any of these were to come adrift or melt or be nibbled, and come into contact with the metal, then the only protective device is the service head fuse, and on TT you can be pretty sure you wont have a low enough Zs to allow enough current to flow to blow it so it will just sit there live all day long. in this instance the 100mA type s gives those internal link wires fault protection, and also maintains discrimination from your 30mA RCCB's.

With a full RCBO board there are none of these internal links so no need for upfront protection, and as somebody mentioned if you use single pole RCBO's and DO fit an upfront 100mA type S RCCB, you havn't got discrimination as the neutral will be left in circuit if the RCBO trips which could trip the 100mA.

In both instances a gland should be used on the incoming tails.

Theres still a tail from main switch to N bar, i will still fit rcd td upfront on TT

 

[suffolkspark]

Theres still a tail from main switch to N bar, i will still fit rcd td upfront on TT

Nothing wrong with that at all as long as your RCBO's are 2 pole.

 

[Dave OCD]

Has anyone ever seen a meter tail or internal link actually become detached and cause a short ? Not only would it have to come out of the terminal/cage clamp it would also have to move considerably. About as much chance of me winning the lottery.

 

[suffolkspark]

Nope, its all overkill like a lot of our regs to be fair

 

[Midwest]

Has anyone ever seen a meter tail or internal link actually become detached and cause a short ? Not only would it have to come out of the terminal/cage clamp it would also have to move considerably. About as much chance of me winning the lottery.

---- happens!

 

[bigspark17]

Nothing wrong with that at all as long as your RCBO's are 2 pole.

Until the cheap sh*t rcbo fails and you have no fault protection on that circuit.

 

[sparksfly]

I have avoided the really cheap RCBOs due to failures in the past incl control gear, I prefer dual RCD with the odd RCBO to keep costs down. I know they are all made to the same BS standard but are all vans made the same !!

 

[Phillip]

Just started on a complete refurbishment / extension on a 3 bedroom property which is having a complete rewire.

I'm not keen on Dual RCD boards, nor trying to have as few circuits as possible ....

So when it comes to the socket circuits I was thinking of:

Radial 20A for hall, lounge and dining room
Ring 32A for kitchen
Radial 20A for upstairs

Anyone like to comment?


PS the plumber was asking me today why I was installing 35 mm boxes - he seemed to think 25 were always best!

 

[Phillip]

Just started on a complete refurbishment / extension on a 3 bedroom property which is having a complete rewire.

I'm not keen on Dual RCD boards, nor trying to have as few circuits as possible ....

So when it comes to the socket circuits I was thinking of:

Radial 20A for hall, lounge and dining room
Ring 32A for kitchen
Radial 20A for upstairs

Anyone like to comment?


PS the plumber was asking me today why I was installing 35 mm boxes - he seemed to think 25 were always best!

Ring up, ring down and ring the kitchen. The cost of a return cable is not worth the mention. As for what back box size, fit the easiest for the job on the day. If the customer decides to have something else fitted later on, which won't fit the box, then you charge according.

 

[Spoon]

Ring up, ring down and ring the kitchen. The cost of a return cable is not worth the mention.

I think the radial has nothing to do with the cost of the cable but some people consider it a safer circuit. I'm sure I'll be corrected if i'm wrong.

 

[richy3333]

In a dual RCCB board you have the brown and blue link leads between the main switch and the RCCB's and neutral bars IF any of these were to come adrift or melt or be nibbled, and come into contact with the metal, then the only protective device is the service head fuse, and on TT you can be pretty sure you wont have a low enough Zs to allow enough current to flow to blow it so it will just sit there live all day long. in this instance the 100mA type s gives those internal link wires fault protection, and also maintains discrimination from your 30mA RCCB's.

With a full RCBO board there are none of these internal links so no need for upfront protection, and as somebody mentioned if you use single pole RCBO's and DO fit an upfront 100mA type S RCCB, you havn't got discrimination as the neutral will be left in circuit if the RCBO trips which could trip the 100mA.

In both instances a gland should be used on the incoming tails.

I'm struggling with your comments, please could you quote your source of reference?

An RCBO board still has an 'internal link' - neutral cable between the outgoing on the main switch and the neutral bar. Utilising your argument what if this came loose/detached? There's also the main tails coming in, what if these came loose/detached, wouldn't the same scenario that you allude to exist?

TIA

 

[richy3333]

The M2 RCBO boards are only around £150 for a 12 way board populated with 10 RCBO's. Short style RCBO's and no stupid fly leads to deal with.

I'm experiencing lots of requests for USB 2G socket outlets so 35 or 47mm boxes for me.

 

[Spoon]

I'm experiencing lots of requests for USB 2G socket outlets so 35 or 47mm boxes for me.

How are these usb sockets these days? I've heard bad reviews. Is testing them ok?
Product recomendation please for Chrome Wall sockets with USB - https://www.electriciansforums.co.uk/threads/product-recomendation-please-for-chrome-wall-sockets-with-usb.121061/

 

[Ian1981]

I'm struggling with your comments, please could you quote your source of reference?

An RCBO board still has an 'internal link' - neutral cable between the outgoing on the main switch and the neutral bar. Utilising your argument what if this came loose/detached? There's also the main tails coming in, what if these came loose/detached, wouldn't the same scenario that you allude to exist?

TIA

This was the argument before non combustible materials where to be used for domestic consumer units.
A metallic constructed consumer unit wasn’t to be used in a TT system but here we are!
All we can do as installers are to try and protect and secure the meter tails as best we can to ensure no loose connections will result in danger to the user or fire.
It’s a principal we should try and achieve in every installation regardless.

 

[bigspark17]

The M2 RCBO boards are only around £150 for a 12 way board populated with 10 RCBO's. Short style RCBO's and no stupid fly leads to deal with.

I'm experiencing lots of requests for USB 2G socket outlets so 35 or 47mm boxes for me.

Where you buying the m2 rcbo board from?

 

[suffolkspark]

I'm struggling with your comments, please could you quote your source of reference?

An RCBO board still has an 'internal link' - neutral cable between the outgoing on the main switch and the neutral bar. Utilising your argument what if this came loose/detached? There's also the main tails coming in, what if these came loose/detached, wouldn't the same scenario that you allude to exist?

TIA

I went to a seminar when the AM3 boards came out (says a lot for my social life) and this is the advice that the IET gave on the day.

The incoming tails on the other hand are meant to be secured so there should be no chance of them becoming detached.

 

[JK-Electrical]

Where you buying the m2 rcbo board from?

I think M2 is CEF's own brand.

I've just tried logging-in to my online account to see how much they're asking for one of these boards only to discover that my account has been de-activated. This would most likely be due to the fact that I've spent no more than £50 at CEF in the last couple of years. CEF are way too expensive. I can buy my materials elsewhere at a fraction of the grossly-inflated prices that CEF are asking.

 

[JK-Electrical]

Just started on a complete refurbishment / extension on a 3 bedroom property which is having a complete rewire.

I'm not keen on Dual RCD boards, nor trying to have as few circuits as possible ....

So when it comes to the socket circuits I was thinking of:

Radial 20A for hall, lounge and dining room
Ring 32A for kitchen
Radial 20A for upstairs

Anyone like to comment?


PS the plumber was asking me today why I was installing 35 mm boxes - he seemed to think 25 were always best!

I'm not keen on Dual RCD boards either and prefer RCBO boards if the job budget permits. I fitted an MK board the other day as this is what the customer specified. Boy oh boy, what a nightmare I had trying to get the lid on. The misalignment of the main switch, RCDs and MCBs was terrible. Never again! In future I walk away if the customer specifies MK products. Oh how the mighty have fallen. MK was once top-notch, but not any more.

As for rings versus radials, I prefer radials over rings where possible.

 

[bigspark17]

4mm radial is close to max ccc depending on installation method especially if theres lots of insulation some would argue its not large enough a conductor to be on 32A ocpd.