Question about 'self made' 12V Lighting in new extension

[davesparks]

they apparently require a certificate that most of you agree is impractical for a non-registered individual to issue.

Who said its impractical for a non-registered person to certify work to bs7671? There must be hundreds of us who aren't registered with any scheme but still certify our work.

 

[Lucien Nunes]

Good contractors would only install material for which they had, or could reliably obtain, traceable approvals. In the event of any comeback, their position is clear regarding the boundary between their responisibilities and those of the manufacturer. If your equipment is CE-marked, it doesn't matter that you made it, you can ask him to install it and his responsibilities are unchanged. Some contractors will however balk at fitting items that they consider less satisfactory than their normal choice. If your equipment does not carry the necessary approvals, e.g. because it's a prototype or demo model, then a contractor might not want to install it.

If you want to install equipment for the supply of electrical energy yourself, then it might need to comply with BS7671. A micropower sensor cable would not, an ELV circuit carrying 10A to lighting fixtures certainly would. The onus will be on you to provide the certification that it does. This should be no problem for you, as you will understand the requirements and can fill in the certificate. However, some would consider the load side of an un-pluggable CE-marked PSU brick not to be part of the fixed installation. If that is in fact the case, then once the electrician has laid on the supply to the brick, you can do whatever you like as far as BS7671 is concerned.

 

[l4urence]

Good contractors would only install material for which they had, or could reliably obtain, traceable approvals. In the event of any comeback, their position is clear regarding the boundary between their responisibilities and those of the manufacturer. If your equipment is CE-marked, it doesn't matter that you made it, you can ask him to install it and his responsibilities are unchanged. Some contractors will however balk at fitting items that they consider less satisfactory than their normal choice. If your equipment does not carry the necessary approvals, e.g. because it's a prototype or demo model, then a contractor might not want to install it.

If you want to install equipment for the supply of electrical energy yourself, then it might need to comply with BS7671. A micropower sensor cable would not, an ELV circuit carrying 10A to lighting fixtures certainly would. The onus will be on you to provide the certification that it does. This should be no problem for you, as you will understand the requirements and can fill in the certificate. However, some would consider the load side of an un-pluggable CE-marked PSU brick not to be part of the fixed installation. If that is in fact the case, then once the electrician has laid on the supply to the brick, you can do whatever you like as far as BS7671 is concerned.

This is an excellent reply - well stated. The only comment I have is whether the OP is in fact the manufacturer, I believe he is and as stated the boundary is clear. Placed in this position consideration would need to be in obtaining appropriate documentation from the 'manufacturer' and detail this in the departures section of the certification and limited as a 'PSU brick'. or some such technical jargon.

 

[Radian]

Good contractors would only install material for which they had, or could reliably obtain, traceable approvals. In the event of any comeback, their position is clear regarding the boundary between their responisibilities and those of the manufacturer. If your equipment is CE-marked, it doesn't matter that you made it, you can ask him to install it and his responsibilities are unchanged. Some contractors will however balk at fitting items that they consider less satisfactory than their normal choice. If your equipment does not carry the necessary approvals, e.g. because it's a prototype or demo model, then a contractor might not want to install it.

Totally understandable. I really don't wish for the contractor to install any of it. It would be trivial work for me compared to explaining how it would be done by someone else anyway. The problem seems to be with having me do some installation alongside theirs when it comes to any third-party inspection.

If you want to install equipment for the supply of electrical energy yourself, then it might need to comply with BS7671. A micropower sensor cable would not, an ELV circuit carrying 10A to lighting fixtures certainly would. The onus will be on you to provide the certification that it does. This should be no problem for you, as you will understand the requirements and can fill in the certificate. However, some would consider the load side of an un-pluggable CE-marked PSU brick not to be part of the fixed installation. If that is in fact the case, then once the electrician has laid on the supply to the brick, you can do whatever you like as far as BS7671 is concerned.

While I was going to power the AC-DC power supply from the lighting circuit (simply because I have a dedicated MCB for the zone containing my own products) I can simply plug-in to an existing 13A outlet in the rack cupboard where the rest of the home-control kit lives.

But you only say some would consider the lights so connected not to be part of a fixed installation. I see nowhere in BS7671 that covers this edge case so I would have nothing in writing to demonstrate this to the contractor.

As for a micropower sensor cable, would it not come within the scope of BS7671 where 100.1.2 describes "fixed wiring for information and communication technology, signalling, control and the like"? The keyword seems to be "fixed wiring" - evidently of any description.

 

[alasdairp]

There is a 60 page IET Code of Practice for Low and ELV DC power distribution in Buildings. I have version 1, published in 2015.

ELV is defined as not exceeding 50 volts AC or 120 volts ripple-free DC (in BS7671). You do need to meet BS7671 as regards to current carrying capacity of the wires, etc, etc, but not any building Regs. as far as I could find out.

Video resources for LV and ELV d.c. power distribution - https://electrical.------.org/wiring-matters/issues/61/video-resources-for-lv-and-elv-dc-power-distribution/

In your case I would get the work signed off without your DC lighting and then add it if afterwards. I can understand a normal sparky being wary of signing off your bits. That is what I did in my own house - in Scotland you have to be a Member of a competent group (e.g. NICEIC et etc) and also on a list of Approved Electricians in Edinburgh to meet the Scottish equivalent of Part P Building Regs. But the ELV DC wiring and fitments do not, as far as I can find out, come under the building Regs.

 

[Andrew B]

Install your bit yourself and ask the contractor to clearly state in his installation certificate the extent of the installation the certificate covers. Which would be a case of identifying the circuit excluding ELV lighting.

 

[Radian]

The first fix is underway and I will be laying in draw-wires to key locations enabling me to install most of my equipment at a later date without too much surgery.

I greatly appreciate the constructive and civil atmosphere of these forums. This is in contrast to some other online trade forums I have visited. Thank you all for taking time to consider my question.