Opinons and advise on new consumer unit.

[sambotc]

Hi,

I am going to have to buy a new consumer unit soon. The existing CU is a wylex metal type with fuse wire's replaced with MCB's.

It is a 4 way box with main switch. the 4 MCB's control lighting ground, lighting first, ring main and cooker.

I am in the process of re-doing the bathroom and a whirlpool bath going in which needs an RCD. I intend to run a cable back to the CU for this and have the bath on it's own trip.
I was thinking about a 6 way CU as i cannot increase the CU as space is tight.

Would ideally like to split the ring main to ground/first but not sure if this is possible as the house has concrete floors and all the wiring goes through first floor so there is no obvious way to identify cables. Any suggestions?

I was thinking along the lines of split box with 2 rcd's or RCBO's. Depends on price really.

Do RCBO's fit the same boxes as MCB's or do you need a specific CU for RCBO's.

What make do the pro's recommend for a small unit, good quality reasonable prices?


Cheers Sam

 

[Lectrician]

Get a 6way MEM, 4 RCBO's, and put the bath on the ring - no need for the extra expense of an extra circuit and breaker.

Top notch job.

A split loader, weather it be 16th or 17th is going to be much wider.

Whats the need for splitting for the ring? I dont see it as an issue worth time to sort. Ideally to comply with the 17th, you should be splitting your circuits left and right rather than up and down.

 

[sambotc]

Hi,

Thanks for the response.

The idea behind the bath being seperate was in case of any down time, service or problems it could be easily isolated. To be honest the CU is the closest place i can pick up the ring anyway so for the extra £20 i could just chuck in another RCBO.

The CU is under the stairs and i have wired a switched fused spur off the ring main to power a light as everytime a bulb went it tripped the MCB and i couldn't see! The only reason i could see splitting the ring was so if the upstairs circuit this light could still be used. Other than that there is no benefit just seemed like a good idea

Just out of curiosity. what reason is there to split left and right?

Will look at MEM units now
Thanks, Sam

 

[Lectrician]

So if you loose a circuit, you loose some upstairs and some down, leaving 50% of both upstairs and downstairs still working. Convenience and safety (dark).

This is more so important with 17th edition dual split boards where you would make sure the left and right are transposed so that if one RCD went you lost sockets on the right but still had lights on the right, and lost lights on the left but still had sockets on the left. For a house with upstairs/downstairs, you would make sure the split was done so if you lost an RCD, you would loose lights up and sockets down and vica versa. This makes no odds if you go for an RCBO filled CU.

Hope that makes sense!

The bath would still require an FCU or DP switch if your RCBO was rated low enough, and this would be your point of isolation, not the RCBO.



MEM are a very good make, but others are more than suitable.

 

[sambotc]

Hi,

Yep that makes perfect sense. Presumably this is for new installations rather than upgrades?

Completly forgot about the FCU (e.g switched fused spur, right?) so yes, i'll save myself a few quid there.

Can the FCU be locaed in the loft space or is this not accessible enough? It is no bother fitting a recessed box into the wall above the bathroom door (externally of course) but would rather not have it all on show if possible. Will also have one for the extractor fan so may look a bit messy.

Will look into other makes too.

Cheers, Sam

 

[ban-all-sheds]

Are you in England or Wales?

 

[sambotc]

Hi,

Yep!

I'm presuming you are refering to Part P notification?

I am actually Part P registered through CORGI although only to levels B&C so the company i work for has a sparky who is level A will be doing the CU work and notifying. I will simply be supplying the gear and installing the cable and spur's.

Cheers, Sam

 

[professional]

If you are installing the cabling and spurs, the spark is breaking the law by certifying the cable runs as he has not installed them himself.

 

[ban-all-sheds]

Not if (as I assume) it's the company they both work for that's certifying his work.

 

[sambotc]

Hi,

Yep thats how it would be notified. Is there an issue in doing it this way?

Cheers, Sam

 

[ban-all-sheds]

No.

 

[sambotc]

Hi,

Thanks for the reply once again.

So can i fit the FCU's in the loft for the bath & extractor or do they have to be readily accessible?

Cheers, Sam