2 module enclosure

[marcuswareham]

I am not sure if this is acceptable?

If I am using a 2 module enclosure for 2 MCBs both fed from a MCB in the main consumer unit. Would I have to use a busbar inside the 2 module enclosure or would it be ok to have a cable link at the bottom of the MCBs.

I have heard people say this is a nono inside a C/U, but my thinking in this example is that as long as the cable is rated high enough for the MCB from to C/U then there shouldn't be a problem as overcurrent protection is provided by the MCB feeding the 2 MCBs

Thanks Marcus

 

[telectrix]

you should have a D/P switch in that unit in order to isolate. therforei suggest you buy one of these. I f fed from RCD on main CU, replace the sub . RCD witha D/P switch.

https://www.NoLinkingToThis/p/british-general-5-module-3-way-populated-garage-consumer-unit/1926g

do it right

 

[marcuswareham]

you should have a D/P switch in that unit in order to isolate. therforei suggest you buy one of these. I f fed from RCD on main CU, replace the sub . RCD witha D/P switch.

https://www.NoLinkingToThis/p/british-general-5-module-3-way-populated-garage-consumer-unit/1926g

do it right

ah ok, so there is a requirement for double pole isolation, cool thanks

 

[marcuswareham]

So if it was a metal 2 module enclosure (like the wylex one available at Screwfix) and it was earthed is that then not alright. not sure there will be space for one of the BG garage c/u

 

[pc1966]

So if it was a metal 2 module enclosure (like the wylex one available at Screwfix) and it was earthed is that then not alright.

What is wrong with that? It should be earthed one way or another, either earth rod if TT or from the feed supply.

not sure there will be space for one of the BG garage c/u

How small is the garage?!

There will always be wall space, unless it is a doll's house!

 

[marcuswareham]

What is wrong with that? It should be earthed one way or another, either earth rod if TT or from the feed supply.


How small is the garage?!

There will always be wall space, unless it is a doll's house!

haha this aint for the garage, this is for a friend's house,

 

[pc1966]

So what is it for? Not enough slots in the CU?!

 

[marcuswareham]

So what is it for? Not enough slots in the CU?!

He has some underfloor heating in the kitchen of a kitchen-dinner, on its own B6 MCB he has added underfloor heating to the dinner part but its total load is just over 1500w so to much to add onto the B6 MCB. The cable for the kitchen underfloor heating is already in and very difficult to replace it is only 0.75 T&E so cant just swap the B6 MCB for a higher rating.

The consumer unit is full up, So a suggestion I said which might work, without ripping all of the plaster down. Was to swap the B6 for a B10 or B16 and then but an enclosure next to the C/U feed from the new MCB via new cable, then a B6 in the enclosure would protect the kitchen floor cable and a B10 for the dinner underfloor heating, on a thicker cable

 

[DPG]

0.75 T&E? .

 

[marcuswareham]

0.75 T&E? .

Ahh yeah, that's what he told me, only been told this stuff as I have not been round there due to the lock-down

But your question made me check and it seems 0.75 not available in T&E, maybe its flex or he has got it wrong and its 1mm, I will check with him

 

[pc1966]

Yes, you could use something like this:

https://www.NoLinkingToThis/p/wylex-ese2-ip40-2-module-unpopulated-din-enclosure/32311

But you would need to allow for earthing the metalwork (no idea if it has a terminal strip inside or not) and you could use Wago for joining the neutrals. Not ideal, but if that is all the space you have...

The preference for a bus-bar comes from a number of factors, reliability is one, the other is most MCB can only take 25mm total conductor, so you could not loop in and out cable for 100A as needed in a CU. But reliability/safety from a good connection is reason #1

 

[davesparks]

The cable for the kitchen underfloor heating is already in and very difficult to replace it is only 0.75 T&E so cant just swap the B6 MCB for a higher rating.

That's going to be a problem then as that's non-compliant with the regulations, and if you disconnect it and reconnect to a new CU then you need to correct such a significant non compliance.

 

[marcuswareham]

Yes, you could use something like this:

https://www.NoLinkingToThis/p/wylex-ese2-ip40-2-module-unpopulated-din-enclosure/32311

But you would need to allow for earthing the metalwork (no idea if it has a terminal strip inside or not) and you could use Wago for joining the neutrals. Not ideal, but if that is all the space you have...

The preference for a bus-bar comes from a number of factors, reliability is one, the other is most MCB can only take 25mm total conductor, so you could not loop in and out cable for 100A as needed in a CU. But reliability/safety from a good connection is reason #1

I see what you are saying,

Yes I was thinking the same wago for the neutrals.

That makes sense about busbar vs cable loops, although just has a thought which maybe is better is to take 2 bits of T&E from the B10 MCB inside the c/u so each MCB in the enclosure is feed from a separate cable

The enclosure you sent me is a plastic one, the metal version of the same thing has an earth terminal inside. Would I be able to use the plastic one, as is it only C/U that have to be metal ??
[automerge]1587503253[/automerge]

That's going to be a problem then as that's non-compliant with the regulations, and if you disconnect it and reconnect to a new CU then you need to correct such a significant non compliance.

I see what your saying, as in the cable is non-compliant, I will have to get confirmation on what is there

 

[westward10]

No offence but it looks like to me you do not have the competence to be undertaking these works.

 

[pc1966]

That's going to be a problem then as that's non-compliant with the regulations, and if you disconnect it and reconnect to a new CU then you need to correct such a significant non compliance.

Yes, well spotted if it is going in to the CU like that as regs have 1.5mm minimum for power.

Quick and dirty would be to put a double 13A socket on that heater breaker (upgraded to 16A) then you would be OK to connect 0.75mm round cable to it via a plug and 5A fuse, etc., and other heater on the other plug.

 

[marcuswareham]

No offence but it looks like to me you do not have the competence to be undertaking these works.

Fair enough, as i have said i work doing temporary power systems so understand the fundimentals but not the nitty gritty of the regs when it comes to domestic, as even though they are both under bs7671 our bit bs7909 is a little different in terms of cable and distribution units

I may not be doing the work, and at the min we are just talking about the options and I am getting information over the phone

I was mainly asking if having 2 MCBs in an enclosure next to c/u would be within the regs. or does it have to be a sub c/u (like the BG one on this tread)

I will have to ask him about the cable, as it is possible he has given me the wrong information or there was a misunderstanding

 

[davesparks]

The enclosure you sent me is a plastic one, the metal version of the same thing has an earth terminal inside. Would I be able to use the plastic one, as is it only C/U that have to be metal ??
[automerge]1587503253[/automerge]


I see what your saying, as in the cable is non-compliant, I will have to get confirmation on what is there

Yes it does have to be metal, there's no way you could suggest that is not similar equipment to a CU.

I'm not sure you do see what I'm saying.

These questions are becoming increasingly concerning that you don't have sufficient knowledge or experience to be doing these works.

 

[pc1966]

The enclosure you sent me is a plastic one, the metal version of the same thing has an earth terminal inside. Would I be able to use the plastic one, as is it only C/U that have to be metal ??

Ah, had not noticed. Would explain why it is so cheap! Here is the metal version and it says it has an earth bar:

https://www.NoLinkingToThis/p/wylex-esm6-ip40-2-module-unpopulated-din-enclosure/666gx

Edit: I see you already know it!

 

[davesparks]

Fair enough, as i have said i work doing temporary power systems so understand the fundimentals but not the nitty gritty of the regs when it comes to domestic, as even though they are both under bs7671 our bit bs7909 is a little different in terms of cable and distribution units

I do both electrical installation work and temporary systems under BS7909 and the two jobs are world's apart.

 

[marcuswareham]

The consumer unit is also behind a draw in the kitchen which to me doesn't exactly seem right to me

have to remove the draw to get to it and there is hardly any working room around it