Workshop wiring query

[kirkpoore1]

Well chaps, just to warn you, I will be coming back with more questions over the coming weeks. Electrician came back wit a quote for over £2,000 to wire up my workshop , so I will be 'insourcing' a lot of work and then looking to get it tested and signed off later.

Terry.

Holy crap, that's nearly what I paid for my shop electrical work, including materials! And mine has a lot more than yours will.

Time to buy a how-to book, I guess, or print a bunch of stuff out from the web...

Kirk

 

[Rob]

or.........ask one or two sensible questions here

 

[AndyP]

Terry,
FWIW I'd rather do electrics than plumbing any day. Providing you can read and follow the specs and regs cutting cables and wiring sockets and lights really is quite straight forward.
I got someone to install the consumer unit in the barn and do the run from the mains supply in the house but that was an add on to other work he had to do in the house and garage ( ie replace the old fuse wire fuse box affair ).

Supposing you put in the consumer unit in the workshop yourself and did all the sockets and lights then prepared the run (underground?) for the mains feed. How much would your electrician charge to do the final connection in house and workshop consumer unit and test your install? Just a couple of hours work?

 

[9fingers]

A little off the wall thought as Andy mentioned plumbing.

Might be worth having a small elevated tank outside for the gutter water to pass through and pipe and tap over a small sink that drains back into the gutter pipe.
A little water to rinse hands, dampen a cloth to take off excess glue etc can be really handy.
Only need to be one of those heating header tanks, tucked round the back out of sight. It might run dry in the summer from time to time but should be enough virtually all year round. Plumb in with garden hose or similar and very little chance of a burst due to ice.

Bob

 

[Wizard9999]

A little off the wall thought as Andy mentioned plumbing.

Might be worth having a small elevated tank outside for the gutter water to pass through and pipe and tap over a small sink that drains back into the gutter pipe.
A little water to rinse hands, dampen a cloth to take off excess glue etc can be really handy.
Only need to be one of those heating header tanks, tucked round the back out of sight. It might run dry in the summer from time to time but should be enough virtually all year round. Plumb in with garden hose or similar and very little chance of a burst due to ice.

Bob

:text-bravo: :text-goodpost:

Oh I do like that idea Bob. :eusa-clap: Current plan is for gutter to run into a water butt, so I could simply put the small header tank in between the roof and water butt. More I think about it, more I like it, top marks that man!

Terry.

 

[9fingers]

Glad you like it Terry! You can have licence free use of my idea :lol:

You can buy the interceptor fittings designed to go into a water butt that deals with the overflow etc and instead of going to a butt, it can go to the header tank.
The sink outlet can drain into nearby soil after all it is only going to be the odd cupful every now and then and either be hand soapy or very diluted glue. If you fit a trap in the sink outlet is will stop a cold draught coming up the plug hole and drown any creepy crawlies.

Bob

 

[AndyP]

Add a water filter and you could be brewing your own tea.

 

[Wizard9999]

Don't forget earth to each fitting include switch back boxes even if they are plastic - its the rules!

Bob

Knew I had seen this comment somewhere. So my question is, what about the boxes I have that have no earthing point in them? :eusa-think:

Terry.

 

[9fingers]

On further searching I cannot find consistent comments about whether or not the earthing terminal in a plastic back box should be earthed.
Clearly if you don't have one then you can't earth it.
Hopefully we can assumed that as back boxes are sold without terminals, they still meet regulations (?)

Are you in contact with the guy you plan to ask to sign off the installation? Maybe ask him to be sure of what he will be looking for.

Apologies if I have been a source of confusion.

Bob

 

[Wizard9999]

On further searching I cannot find consistent comments about whether or not the earthing terminal in a plastic back box should be earthed.
Clearly if you don't have one then you can't earth it.
Hopefully we can assumed that as back boxes are sold without terminals, they still meet regulations (?)

Are you in contact with the guy you plan to ask to sign off the installation? Maybe ask him to be sure of what he will be looking for.

Apologies if I have been a source of confusion.

Bob

Bob

Never apologise for being helpful!

I have finally found somebody at least willing to consider doing the connection to the workshop, I think the job is too small for most electricians to bother with and I hope he will be coming today to take a look. I think I will just leave things as they are, if on inspection he says the boxes need earthing well I'll just have to do it then, as you say an odd requirement as Toolstation boxes do not have earth connections.

While I have you, can I also just double check on what I plan for the consumer unit:
Lighting circuit 1 (single fitting above door): 6amp type B breaker
Lighting circuit 2 (six double flourescent fittings): 6amp type B breaker
16amp radial socket 1: 16amp type C breaker
16amp radial socket 2: 16amp type C breaker
Main power ring main (7 double and 1 single sockets): 20amp type B breaker

Is this correct, and if it is would it be an option to use 32amp type B for the main power ring?

Thanks again for all your help on this.

Terry.

 

[9fingers]

Hi Terry,

I'm unsure if the bank of fluorescents will trip the B6 breaker as they all start at once. You could easily swap it for a B10 later if it caused trouble. If the lights have multiple switches (which I did think you or someone talked about at one stage) then B6 should be no problem.
I've got 5 x 5foot doubles with high frequency ballasts (possible more gentle than a simple iron choke ballast) all starting at once that don't pop 5 amp old fashioned fuse wire but that is very tolerant of short term overload.

It would be more normal to use a B32 on a ring main assuming it is wired with 2.5mm - remember the fuse/breaker is there to protect the wiring not the appliance plugged in.
Was there a specific reason for suggesting a B20?

Bob

 

[Rob]

Echoing Bob's comments about B32 vs B20 Terry...I'm thinking of heating in the winter. At some point you will inevitably have either an oil filled rad or even a fan heater or some such so the load on the mains needs to have that capacity. Also, you never know what else that building will get used for in time (den for teenage kids if you change use later...million possibilities). So I'm just saying leave plenty of ampage capacity for heating. Hopefully your efforts in insulation will make that requirement very small.

 

[RogerS]

Interestingly when I wired up the building that was later to become my workshop, I wired up three separate rings. One ring went down the length of one wall, and the other two went down the length of two of the other walls. I planned to use the of of these two rings for heaters and had a contactor fitted driven by a thermostat. So the idea being that when the room got cold (it was going to be a gym ) the thermostat would kick in, switch on the contactor which would then power the heaters on the ring. This would leave me two other rings for other things. Quite what I might have plugged in to draw so much current I was never really sure but....easier to put in when the wall are just studs.

When I 'adopted' the gym, the second ring became very useful for feeding my 16A stuff., the contactor being permanently energised.

 

[Wizard9999]

Mention of 20amp was just my poor recollection of what had been said before. electrician immediately said, right two 16amp, two 6amp and one 32amp. The 16amps will be C breakers and the others B breakers. The fluorescents are split three and three on two switches, so I guess only risk is if I hit both at the same time. Now just waiting for the quote, bit twitchy after the previous electrical quote, but frankly not much choice here, I'm not touching the mains and he is the only person who seems interested in the work, not that I told him that of course . It will get signed off for Part P as he said he would have to check all the wiring if he was wiring in the consumer unit anyway.

I recall somebody (Mike I think) mentioned that to do your own wiring and have it signed off you have to be "competent". Glad I knew that when he casually asked, so what experience do you have of electrical wiring, without having seen that comment I would have said "me, can't even tell the difference between an amp and a volt", instead I waxed on about my father being an electrician (true) and how I helped him retire multiple houses (less true), oh and I did mention lots of expert input, just the way I phrased it may have lead him to believe you had all been to my workshop multiple time!

Anyway, sure I have said it before, but, I really appreciate everyone's advice and tolerance of my stupid questions :eusa-clap: .

Terry.

 

[Mike G]

........ I really appreciate everyone's....tolerance of my stupid questions :eusa-clap: .

Terry.

I haven't seen any of those. It's good to watch someone building a workshop with pride.

 

[Rob]

I tell you what Terry, you may be relatively new to all this but I wouldn't apply the word stupid to anything you've done! Dedication, endeavour, good planning and thorough and intelligent research I might coupled with a good dose of old fashioned British spirit.

 

[stephen.wood125]

I've seen nothing stupid!!

Great thread, really good to see what looks like a really thumping workshop coming together.

Inspirational and interesting. Bravo! :text-bravo: bscene-drinkingcheers:

 

[Wizard9999]

OK, estimate back already, he must be keen.

He has estimated £500 all in. Not sure what I was hoping for, but it still feels like a lot of money, I guess in part because apart from the concrete I have done everything else so it has only ever been materials I have paid for. This quote is for materials and doing all the work, in short it covers:
- split tails from meter and add a 100mA RCCB with 40A MCB in meter cupboard*
- this unit to be fitted inside a lockable metal case (so I can control if power is running to workshop)
- run armoured cable through garage and across walkway to workshop (about 10m in total)
- fit 8 way consumer unit with 30mA RCD and 5 appropriate MCBs (3 spaces will be left for expansion)
- check my wiring and provide certification for whole installation

I have little choice, I do not feel comfortable doing this myself. I guess of the £500 I reckon at least £100 must be materials, so it is costing my £400 for the work, including the peace of mind that nothing I have done will end up killing me. In typing this I have convinced myself this is money well spent. I'll just think about the original quote of £2000 plus VAT and smile aout the £1700 I have saved by buying and fitting all the sockets, switches and lights myself.

One question I do have is, do you think a 40 amp MCB in the protection between meter and workshop is sufficient?

Terry.

* I already new cables could not be run straight from the meter, as the regs limit tails to a max of 3m.

 

[9fingers]

40 amps should be fine. Possibly make it type c? See what he reckons once he has tested your earth. The earth impedance has to be lower (better) for type c breakers.
Price does not seem unreasonable all in all.

Bob

 

[RogerS]

Terry, don't under-estimate the cost of the materials. I reckon that you're probably looking at closer to £200 if I read your BoM correctly.

Roger

 

[StevieB]

+1 - those material costs are not as cheap as you think.

Steve

 

[Wizard9999]

Thanks for the feedback chaps. Electrician duly given the go ahead, hopefully will be here a week Monday. Roll on power in the workshop.

Terry.

 

[Rob]

Great news Terry

I'm guessing from the subtext that Ricky didn't come good in the end? Did he even return your call?

 

[TrimTheKing]

All looking positive Terry and have more faith in yourself. As the saying goes, if you don't know something then "The only stupid question is the one you don't ask!"

Cheers
Mark