Do I need a new CU?

[richardrich79]

Untitled

• richardrich79
• 23 Oct 2013
• 1

I want to add a new 10mm cable to this , as per previous thread the cable is going to be laid in conduit so the electrician can see the whole length and wire one end to this cu t'other to shower.
First guy said £100, next guy seemed to feel sorry for me as I'm disabled (=skint) said he'd do it for a 'drink'. Great but as I'd already asked 3 to quote the final guy said, after much suckin of gums etc, it needs a new whole CU plus all the frigging about that goes with it and will cost 'a lot'.
Anyone can see there's 2 empty slots there, so. Can you add a new (whatever size a 10.5kw shower needs) without ripping the whole thing out?
The last guy wasn't an indi but works for a national company.

 

[davelx]

I can't see why you need a new CU - should be possible to add a 50A RCBO (though a 40A would be fine in practice, it's not strictly compliant as 10.5kW is just under 45A) to the non-RCD protected side (shift the others one slot to the right so that the highest current device is next to the mains switch).

 

[Chri5]

Use an rcbo on the none rcd rail, as mentioned shift the three existing circuits over and make the rcbo the first circuit.

The installer will need to buy some more copper rail to interlink the live on the main switch over to the rcbo and the three mcb's. A Crabtree rcbo is about £26

 

[Spark123]

I think this is a Crabtree Starbreaker CU, the MCBs or RCBOs push onto the bus bar - you don't need another bus bar.

I think these are the MCBs and RCBOs for your unit:
http://www.tlc-direct.co.uk/Main_Index/Consumer_Units_Index/Crabtree_Starbreaker_MCB/index.html
Your electrician should be able to advise.
BTW - what is the B40 being used for - the cooker?

 

[Getoffmyland1]

This work should not be undertaken lightly, its scoped under Part P which means only a competant person can undertake it then, certificate the work, then register with the local council via either NIC/EIC or ECA etc. Large fines await if found out -----------YOU HAVE BEEN WARNED.

 

[JohnW2]

This work should not be undertaken lightly, its scoped under Part P which means only a competant person can undertake it then, certificate the work, then register with the local council via either NIC/EIC or ECA etc. Large fines await if found out -----------YOU HAVE BEEN WARNED.

A new forum policeman? Beware, you might create jealousies! If we are to believe anything we have been told (in this and other threads) the OP hasn't got the slightest intention of undertaking this work himself.

.. and welcome to the forum!

Kind Regards, John

 

[AndyPRK]

So how many fines have there been so far ? approximatly ?

 

[JohnW2]

So how many fines have there been so far ? approximatly ?

For failure to notify electrical work? It's hard to be precise, but I believe that, at the last count, it was approximately zero.

Kind Regards, John

 

[Chri5]

I think this is a Crabtree Starbreaker CU, the MCBs or RCBOs push onto the bus bar - you don't need another bus bar.

I think these are the MCBs and RCBOs for your unit:
http://www.tlc-direct.co.uk/Main_Index/Consumer_Units_Index/Crabtree_Starbreaker_MCB/index.html
Your electrician should be able to advise.
BTW - what is the B40 being used for - the cooker?

Never used Crabtree. Zoomed in on the picture and the back bar has slots in it which I assume connect the live to the mcb or rcbo.

Out of curiosity how do the bars get configured for say 3 + 7 rather than generic. 5 + 5 (or can't they be adjusted) ?

 

[JohnW2]

Out of curiosity how do the bars get configured for say 3 + 7 rather than generic. 5 + 5 (or can't they be adjusted) ?

IIRC, they can't be adjusted - but it's quite a long time since I handled one, so I may be wrong.

Kind Regards, John

 

[LearningSpark]

Will a 10mm cable be OK for a 10.5kW shower if the cable is to be installed in conduit?

 

[JohnW2]

Will a 10mm cable be OK for a 10.5kW shower if the cable is to be installed in conduit?

Yes. If the conduit is 'on a wall' then the CCC is 52A, which is more than enough. Even if it were buried in insulation, the CCC would still be 43A or 44A (depending on which Table in the regs one uses!) - and given that "a 10.5kW shower" almost always means 10.5kW at 240V (hence probably only about 9.6kW at the design voltage of 230V), the current demand at the design voltage of 230V will be appreciably below that (around 41.7A).

I can't say I have personally ever heard of anyone using cable >10mm² (i.e. 16mm²) for a shower, but maybe it sometimes happens.

Kind Regards, John

 

[ban-all-sheds]

This work should not be undertaken lightly, its scoped under Part P

There's nothing special about this work in that respect - Part P applies to all work on fixed electrical cables or fixed electrical equipment located on the consumer’s side of the electricity supply meter which operate at low or extra-low voltage and are—
(a) in or attached to a dwelling;
(b) in the common parts of a building serving one or more dwellings, but excluding power supplies to lifts;
(c) in a building that receives its electricity from a source located within or shared with a dwelling; or
(d) in a garden or in or on land associated with a building where the electricity is from a source located within or shared with a dwelling.

which means only a competant person can undertake it

Same as any electrical work.

then, certificate the work, then register with the local council via either NIC/EIC or ECA etc.

Surely you are aware that there are other options?

 

[Satori]

BAS I doubt the self-proclaimed cyber sergeant is aware of the route made available to certain disables persons¹ by regulation 4 of the Building (Local Authority Charges) Regulations 2010.

¹The OP in his opening post refers to his being disabled.

 

[flameport]

IIRC, they can't be adjusted - but it's quite a long time since I handled one, so I may be wrong.

Correct - they cannot be adjusted.
If the supplied configuration isn't what you want, buying a whole new busbar assembly is the only option, assuming the configuration you want is actually available.

If Crabtree must be used, the Loadstar range is better, as that has normal busbar with screw connections on the devices.