Combi Boiler Cable for outdoor lights

[Deleted 100157]

I have recently had a new combi boiler installed in a new location with a direct feed from the CU. The power supply to the location of the old combi boiler (direct feed non-RCD) was no longer required but was in a very convenient location to re-use for external 'low voltage' lights.

The floor is being laid last this week so to try to make the power supply usable I have moved the direct feed to an air brick and connected into a IP65 box with a single cable double live running to a light switch inside for switching.

I will almost certainly get an electrician in to connect the external lights but until then and before the floor is laid can anyone please confirm.
- Is what I have done OK?
- Would there be a requirement for the electrician to change anything at the CU?
- Does anything need to be changed to run the low voltage lights direct from the switched feed in the IP65 box?

Thanks for your advice.
Dave

 

[Deleted 100157]

At the CU the run is connected to a 20A MCB, not rcd protected.
If I am running low voltage out door lights with transformers in an IP65 box, do I need to RCD protect the circuit and if so, does it mater whether it is at the CU or using an RCD spur?
Any thoughts appreciated,
Dave

 

[Veglen]

I suspect you have a 2.5mm T&E radial circuit on the 20A MCB? If so, in order to use this cable for outside you will require 30mA RCD protection at some point.

You must provide protection before the cable exits the building. This can be done by either RCBO, at the CU, if one is available. Or an RCD protected FCU as you have mentioned or even an RCD protected socket outlet.

If the supply to the outside of the house is going to be via fixed wiring i.e permanently connected to the CU or FCU then Part P of the building regs will also have to be followed!

V

 

[RF Lighting]

I suspect you have a 2.5mm T&E radial circuit on the 20A MCB? If so, in order to use this cable for outside you will require 30mA RCD protection at some point.

You must provide protection before the cable exits the building. This can be done by either RCBO, at the CU, if one is available. Or an RCD protected FCU as you have mentioned or even an RCD protected socket outlet.

Where does BS7671 state that?

 

[Veglen]

Well correct me if i'm wrong but the OP wants to use an existing cable to supply outside lighting.

Does this not require RCD protection?

V

 

[RF Lighting]

Thats what I'm asking you.

 

[Deleted 100157]

Thanks very much for your response. It is definitely a 2.5mm T&E radial circuit on the 20A MCB.

I don't believe there is an RCBO so I now see two options:
1. I can place a 30mA RCD under the floor but accesible from the outside through the Airbrick. In this way it is before the cable exits the building but is still accessible. This option would not require an electrician other than for inspection.

2. The circuit is moved to the RCD side of the CU where there are currently 3 x 32A circuit breakers unused. Being a realistic DIY'er, this is something I would leave to an electrician which means money!!

It is a fixed permanent wire from CU to the outside of the house so I guess that means Part P has to be followed. I don't know much about this so if anyone can help, in particular, is the work notifiable? I presume it will need certifying?
Thanks
Dave

 

[Deleted 100157]

OK, I have done some more reading and I understand that it would be notifiable if I did it myself and then I would need the work certified. Of course this is probably more expensive than just getting an electrician to do the work and certify it at the same time so I think I might go for this option with the RCD at the CU. This RCD would also be cheaper and more accessible than a spur RCD under the house.

Any other ideas, advice or help?

Thanks
Dave

 

[RF Lighting]

External lighting circuits do NOT require RCD protection.

Unfortunaly Veglen has fed you mis-information which would have caused you unnecessary work and expense.

 

[ban-all-sheds]

But if that external box contains sockets for wall-warts, then RCD protection is required....

 

[Deleted 100157]

OK, I have done some more reading and I understand that it would be notifiable if I did it myself and then I would need the work certified. Of course this is probably more expensive than just getting an electrician to do the work and certify it at the same time so I think I might go for this option with the RCD at the CU. This RCD would also be cheaper and more accessible than a spur RCD under the house.

Any other ideas, advice or help?

Thanks
Dave

 

[Deleted 100157]

Yup, I am definitely confused so I will summarise the situation and hopefully someone can confirm one way or another.

- Terminal 20A 2.5mm T&E from CU (without RCD protection) direct to IP65 connection box mounted outside airvent. Used to be a dedicated combi boiler circuit that is no longer needed.
- Single 2.5mm T&E from IP65 connection box to light switch to provide switched live.
- Will add 3 x sets of low voltage lights with their transformers in a larger IP65 box which comes with a 4-way trailing extension socket (for the transformer plugs).
- 1m of ducted flex to connect the trailing socket to the switched live in connection box.
- Will not be adding any mains voltage lights, sockets etc.

Questions:
Does this need an RCD?
Does this work need to be certificate?
Are there any problems with the plan above?


Thanks
Dave

 

[ban-all-sheds]

- Will not be adding any mains voltage lights, sockets etc.

Yes you will:

a larger IP65 box which comes with a 4-way trailing extension socket (for the transformer plugs).

Does this need an RCD?

Yes.

Does this work need to be certificate?

Yes.

Are there any problems with the plan above?

Yes - the use of T/E outdoors, and (probably) unsuitable protection for the cable to the sockets once you've removed the plug (i.e. I doubt it's rated for 20A).

 

[Deleted 100157]

Thanks for your help, so a definite electrician job then, just as well I have one coming over tonight to look it over.

I guess your answer does raise a quick question .... if I don't use the trailing socket but cut plugs off transformers and use a suitable amperage connection box with suitable cable and protection from the larger IP65 box back to the smaller IP65 connection box, does this then mean no RCD required?
Thanks
Dave

 

[Veglen]

External lighting circuits do NOT require RCD protection.

Unfortunaly Veglen has fed you mis-information which would have caused you unnecessary work and expense.

Okay RFL,

Not sure I like your tone BTW.

I thought the OP was about to supply outside lighting by way of a transformer connected to a 13A plug top which a socket outlet would be required. This then could be used for portable equipment too!

However, it would appear that I miss read the OP and therefore miss informed him too. And to the OP I apologise.

Going back to the question. Outdoor FIXED equipment is not required to be protected by an RCD. AS RFL has stated. However, a reduced disconnection time of 0.4 sec is required for Class 1 equipment!

That said, because of the way you are intending to supply the outside lighting I would still advise RCD protection and leave the plug tops on!!!


V