Can I put two ring mains into the same fuse in the cu?

[trwb99]

Hi,

I have added an additional ring main to my kitchen - one serves the left hand side, the other the right. Is there any reasn these cannot be wired into the same fuse on the consumer unit?

Cheers

Tom[/list]

 

[andy]

providing the MCB is appropriatly rated for the circuits, then you can.

 

[Adam_151]

While not immediatly dangerous in most cases, each circuit should be connected to its own fuseway, unlike a radial branched at the CU where it can be argued that its only one branched circuit as opposed to two, the same argument can't be used for rings, you can't branch a ring, so its clearly two circuits on the same fuseway, which isn't the correct way to do things and is a bodge

 

[dingbat]

I have added an additional ring main to my kitchen - one serves the left hand side, the other the right.

I'm a little concerned whether you actually mean you have two rings or two radial circuits. The latter would be a normal arrangement if it is impossible to form a complete ring final circuit

Is there any reasn these cannot be wired into the same fuse on the consumer unit?

It is not adisable to have more than one circuit protected by a single overcurrent device, but what is more important is that the overcurrent device is suitable for the design current of the circuit it is protecting (as andy mentioned). Are you absolutely certain that this is the case?

Given that you have a fuseboard, which may mean your installation is quite old, are you also certain that your earthing and bonding are up to the required standard?

Also, by not providing RCD protection (I've yet to see a fuseboard installation with RCD) for the additional sockets you are contravening the wiring regulations. As a result you are effectively contravening the building regulations regarding notifiable works in a special location. This may become significant should you wish to sell your house after next year.

 

[ban-all-sheds]

As a result you are effectively contravening the building regulations regarding notifiable works in a special location.

Assuming he's in England or Wales, then even if the earthing and bonding are OK, and even if there is an RCD, and even if all the caveats about 2 circuits on one fuse/MCB are OK, my guess is that he'd still be in contravention because of failure to notify....

 

[plugwash]

if a cuircuit is seperate all the way back to the CU i would say it should be on a seperate fuse/breaker to reduce both the likelyhood of an overload trip the disruption caused in the event of a trip though the exact regs that pertain to this are clear as mud.

There is nothing dangerous about having two rings starting from the same breaker providing the total loading is sufficiantly low but it is also not a conventional cuircuit arrangement.

some sparkies advise connecting the rings end-end to give a more conventional cuircuit arrangement but this would increase power losses and also increase the chance that the cuircuit would be to long to meet the volt drop and disconnect time requirements.