Consumer unit to small

mark085

Wiring a consumer unit but there's not with room on the din rail, can you put a tiny cu beside it just to support 1 MCB and would it be compliant with the regs?
Any feedback appreciated

Tuco88

Are you not ment to have ~15% space for expansion? Maybe a larger C.U is in order?

Tho I don't know it's situation/location, I couldn't see anything wrong if it's in a suitable enclosure.

meercat

The new enclosure must comply to current regs 2.25mts to the top I'm afraid

2011

meercat wrote: »

The new enclosure must comply to current regs 2.25mts to the top I'm afraid

Really? This is a modification to an existing board, I would doubt that new regulations can be applied retrospectively.

If I were doing this I would replace the enclosure with a larger enclosure rather than having a small board mounted beside the existing. That way it would not look like an after thought. Obviously this would cost more as it would take longer, but ultimately it would be a better job. It would also mean that there would be plenty of space for future additions.

studdlymurphy

Tuco88 wrote:

Are you not ment to have ~15% space for expansion? Maybe a larger C.U is in order?

Would this not be considered the expansion? Even though it seems to be more than 15% expansion of there isn't enough room

Tuco88

Maybe I miss understood the op. Are you just adding a circuit to an existing DB that is full ?

If that's the case the I can't see anything wrong with a suitable enclosure placed next to it.

If it's a new DB there is a rule for space I think it's 15% or greater I'll have to check the regs.

I would agree with 2011, better job to install a larger unit if that's practical to do.

meercat

2011 wrote: »

Really? This is a modification to an existing board, I would doubt that new regulations can be applied retrospectively.

If I were doing this I would replace the enclosure with a larger enclosure rather than having a small board mounted beside the existing. That way it would not look like an after thought. Obviously this would cost more as it would take longer, but ultimately it would be a better job. It would also mean that there would be plenty of space for future additions.

Sorry, to clarify
If he's adding a small sub board to fit a new tripswitch then this board must comply to current height regs

530.5.3
Got a breach of that exact Reg on my inspection report for wiring a shower rcbo enclosure and mounting it beside existing db
It was done for neatness but I had to reposition it.

Tuco88

Is a double module enclosure classed as a DB so?
Could be a costly job to add an rcbo to a full board so.

2011

meercat wrote: »

Sorry, to clarify
If he's adding a small sub board to fit a new tripswitch then this board must comply to current height regs

Ok, I can see your point.
So all the more reason to go with what I suggested:
If you change the enclosure for a larger one then there is no sub-board. There is just one larger board.

meercat

Tuco88 wrote: »

Is a double module enclosure classed as a DB so?
Could be a costly job to add an rcbo to a full board so.

It was by my inspector

meercat

2011 wrote: »

Ok, I can see your point.
So all the more reason to go with what I suggested:
If you change the enclosure for a larger one then there is no sub-board. There is just one larger board.

Yeah I agree it has its advantages but you could be adding huge expense if mains cables and earthing have to be upgraded too and the whole installation tested and certified
There may be an additional cost of €180 to Esbn too

2011

meercat wrote: »

Yeah I agree it has its advantages but you could be adding huge expense if mains cables and earthing have to be upgraded too and the whole installation tested and certified
There may be an additional cost of €180 to Esbn too

Whether a small enclosure installed beside the board or a larger enclosure is fitted, in reality it is just semantics. This should not drive the larger mains cables or an earthing upgrade.

meercat

2011 wrote: »

Whether a small enclosure installed beside the board or a larger enclosure is fitted, in reality it is just semantics. This should not drive the larger mains cables or an earthing upgrade.

If you replace the main cu with a larger one then you have to upgrade the main cable and ensure earthing conforms

2011

meercat wrote: »

If you replace the main cu with a larger one then you have to upgrade the main cable and ensure earthing conforms

I'm just playing devils advocate here, but:

What if only replace the enclosure was replaced?
What constitutes a consumer unit?
Surely an empty plastic enclosure with no MCBs, busbars, fuses or any electrical connections whatsoever can not be defined as a consumer unit.

It would seem extraordinary to me that the act of changing an enclosure for a panel should mean that the mains cable size should be increased.
If that were the case would it mean that like for like replacement of a broken enclosure would mean that the mains cable should be upgraded?
I can certainly understand that adding to the load on any cable could result in the cable size, but that i a separate issue.


Besides, if the mains cable for a distribution board is undersized or the earthing is not up to scratch I would be reluctant to add any additional load to it.

meercat

2011 wrote: »

I'm just playing devils advocate here, but:

What if only replace the enclosure was replaced?
What constitutes a consumer unit?
Surely an empty plastic enclosure with no MCBs, busbars, fuses or any electrical connections whatsoever can not be defined as a consumer unit.

It would seem extraordinary to me that the act of changing an enclosure for a panel should mean that the mains cable size should be increased.
If that were the case would it mean that like for like replacement of a broken enclosure would mean that the mains cable should be upgraded?
I can certainly understand that adding to the load on any cable could result in the cable size, but that i a separate issue.


Besides, if the mains cable for a distribution board is undersized or the earthing is not up to scratch I would be reluctant to add any additional load to it.

Yeah
If you replace the consumer unit then you have to ensure mains and earthing are up to regulations
If you add a small enclosure to the installation than you can issue a notice of potential hazard

Tuco88

Will that small enclosure still have to apply with the current height regs?

I'm sure you said it does already, I go brain dead on weekends...

meercat

Tuco88 wrote: »

Will that small enclosure still have to apply with the current height regs?

I'm sure you said it does already, I go brain dead on weekends...

Yes it does