Garage wiring - CU with greater capacity than submain?

[333rocky333]

£35 pound gets you a 4 way metal board with 100amp mainswitch, a 6a rcbo £13 and maybe a 20a or 32a rcbo is sufficient £13 plus blanks
Contactum is fine for a garage.
Likely you could wire your lights and switch back to it and 3 plate the wiring all within the enclosure.
Bear in mind sometimes large power tools trip 20a on start surge

 

[winston1]

I'll have to do some research into running the lighting off an FCU. I need three separate sets of lights, could I run a 1.5mm2 lighting ring off an FCU? Or take a new spur for each set?

Lights are not run in rings. But you could run all 3 sets of lights off the FCU. A 5 amp fuse will give you in excess of 1 kW of lighting, far more than you'll need. You don't need 1.5mm cable either. 1.0mm is more than adequate and cheaper and uses less of the planets resources of valuable copper.

 

[ChrisZx]

Lights are not run in rings. But you could run all 3 sets of lights off the FCU. A 5 amp fuse will give you in excess of 1 kW of lighting, far more than you'll need. You don't need 1.5mm cable either. 1.0mm is more than adequate and cheaper and uses less of the planets resources of valuable copper.

Ah yes, amateurs again

 

[ban-all-sheds]

The metal, or rather non combustable, which of course metal is not, applies to domestic premises. It is debatable whether it applies to garages.

No it isn't.

 

[ban-all-sheds]

Ah yes, amateurs again

Chris - you really, really, REALLY need to take a step back and spend some proper time learning things from the basics up.

You cannot go ahead with this work on the basis of asking random questions about things which happen to occur to you.

 

[Taylortwocities]

Chris’s, you obviously have taken the DIY option with your LABC. At the end of this you will need to prove to them that what you have done meets the requirements of BS7671. This means DESIGN, INSTALLATION and TESTING.
You are giving to have real problems doing that if you need to ask very basic questions on an Internet forum.

 

[Jackrae]

Well, if you're going to be doing light critical tasks with angle grinder in there you need to invest in maintained lighting. Separation of circuits is to minimise inconvenience and I don't think they class loss of fingers as an inconvenience. If there's a power cut it'll all go off anyway unless it's backed up

'Non-maintained' lighting might be a more desirable option, otherwise the garage would be permanently illuminated.

 

[ChrisZx]

Chris - you really, really, REALLY need to take a step back and spend some proper time learning things from the basics up.

You cannot go ahead with this work on the basis of asking random questions about things which happen to occur to you.

That's exactly what I'm doing! I'm not starting until I've got everything figured out. I haven't really looked at lighting circuits yet, hence the stupid question. Normally I would have looked into it more first before posting but I was busy.

Chris’s, you obviously have taken the DIY option with your LABC. At the end of this you will need to prove to them that what you have done meets the requirements of BS7671. This means DESIGN, INSTALLATION and TESTING.
You are giving to have real problems doing that if you need to ask very basic questions on an Internet forum.

I'm not sure I will have to prove much actually. They are the ones doing the testing and inspecting the installation so sounds to me like it's up to them to satisfy themselves. I don't think they're going to just swing round and take my word for it! They have said they will inspect wiring installation (with nothing connected) when I'm ready but haven't asked for anything else like a formal design.

 

[ChrisZx]

On that note, I was wondering last night if you can take two radials off of one mcb? Or in my case the rcd. I can't really think how it would be any different to a branch in the radial at any other point, or a junction box just below the rcd. It would simplify the wiring in my case.

 

[John D v2.0]

On that note, I was wondering last night if you can take two radials off of one mcb? Or in my case the rcd. I can't really think how it would be any different to a branch in the radial at any other point, or a junction box just below the rcd. It would simplify the wiring in my case.

Yes that's fine, as you say it's the same as any other radial.

 

[ban-all-sheds]

That's exactly what I'm doing! I'm not starting until I've got everything figured out.

It looks as if your "figuring out" consists of asking random questions about things which happen to occur to you, rather than sitting down with books and other reference/educational material and reading about everything.

 

[JohnW2]

I'm not sure I will have to prove much actually. They are the ones doing the testing and inspecting the installation so sounds to me like it's up to them to satisfy themselves.

That's true in terms of the inspection and testing. However, if they are not happy with the way you have done things (i.e. the "design"), the result of the inspection would presumably be that they would tell you to change it (or 'do it all again'), in which case, apart from the hassle, there might be a further charge for further inspection and testing.

Kind Regards, John

 

[ChrisZx]

It looks as if your "figuring out" consists of asking random questions about things which happen to occur to you, rather than sitting down with books and other reference/educational material and reading about everything.

I nearly ignored you but it irked me that this is quite obviously and demonstrably wrong as I started this thread asking very specific questions about a specific section of the perfectly reasonable part-formed plan I had at that time. The plan changed and we started talking about something else, something I haven't looked into yet and didn't have time to research right that second but decided to ask some more questions anyway as other users were being so helpful. There is absolutely no randomness whatsoever.

I've found it difficult to word this bit but based on this and previous posts you seem to think electrics so complex that no layman can understand them, nor identify the right questions to ask in order to fill the gaps in their knowledge. All I will and can be bothered to say is that I have the utmost confidence in my ability to gain the knowledge required and determine whether I know enough to consider my design and installation plans completed. The knowledge itself is fairly easy to come by, as demonstrated by the kind souls contributing to this thread.

That's true in terms of the inspection and testing. However, if they are not happy with the way you have done things (i.e. the "design"), the result of the inspection would presumably be that they would tell you to change it (or 'do it all again'), in which case, apart from the hassle, there might be a further charge for further inspection and testing.

Kind Regards, John

Perfectly true, a known risk I have taken willingly and I don't regret it. The whole point of this thread is to try and mitigate that risk rather than discuss whether I've got two brain cells to rub together!

 

[John D v2.0]

I've found it difficult to word this bit but based on this and previous posts you seem to think electrics so complex that no layman can understand them

To be honest you've done well, most people don't make it past page 1 before getting that reply

 

[ban-all-sheds]

I've found it difficult to word this bit but based on this and previous posts you seem to think electrics so complex that no layman can understand them, nor identify the right questions to ask in order to fill the gaps in their knowledge

If only you realised how laughably, ironically, untrue that assertion is.