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Electrical help / advice please

workshop new build

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Dave C19/12/2016 20:48:31
101 forum posts
12 photos

Hi guys

I have just finished building my new workshop and all has gone well so far but I have one or two electrical issues. I have installed several lights inside which go to a 2 gang light switch. I am quite happy with wiring up one side of the switch as it is just a switch wire from the central light however the other side of the switch is confusing me.

I have 2 external lights which each have a cable coming straight into the light switch and also the cable from the consumer unit. Therefore I have 3 cables to wire to one side of the light switch.

I have managed to totally confuse myself, any offers please.

Also if there are any electricians in the Swinton Manchester area able to help out installing a breaker in my house to supply the workshop I would be only too pleased to hear from you. The breaker is to supply my garage with the already run 16mm cable. (Needed for welding etc 60amp ????? ) there's then a 10mm cable which extends to my small workshop, (consumer unit already installed but not connected.)

I would be happy to pay the going rate for any assistance. I have asked quite a few electricians but they are all either too busy or uninterested in a small job.

Many thanks in advance

 

 

 

Edited By Dave C on 19/12/2016 20:50:01

Paul Lousick19/12/2016 21:01:39
2078 forum posts
728 photos

Hello Dave,

Not sure of laws in UK but here in Aus. electrical and plumbing work has to be done by a licenced tradesman.

Eectricity can be lethal and fawlty wiring can cause fires which would not be coverred by house insurance.

Paul.

Emgee19/12/2016 21:04:18
2445 forum posts
291 photos

Hi Dave

Connect the 3 blue conductors together in a terminal block.

Connect the brown from the consumer unit into the 2nd common on the switch.

Connect the 2 brown conductors from the lights into the other switch terminal, you may have a 2 way switch so the os lights may come on with the switch showing off, if this happens just connect to the other switch terminal.

If there are 2 circuits in the switch make a small label to warn others of 2 circuits in switch.

Emgee

edited typo

Edited By Emgee on 19/12/2016 21:05:24

Dave C19/12/2016 21:15:20
101 forum posts
12 photos

Hi Paul I totally agree that the wiring should be done by a qualified tradesman and I in no way mean to degrade them by attempting this myself. The complete installation will be checked and approved prior to use but as I built the workshop from the ground up I also wanted to do as much as possible myself and hopefully learn something along the way.

Emgee many thanks for your help, the switch has one terminal at the top L and two at the bottom L1 and L2. ???

Edited By Dave C on 19/12/2016 21:15:56

Ajohnw19/12/2016 22:13:36
3631 forum posts
160 photos

The method of wiring them is shown here

**LINK**

It was done with ordinary twin and earth but either wire can be live in this case and neutral will carry it in one setting. I don't think that has changed.

A welder I recently bought goes up to 120 amps but as far as the plug is concerned it's still ok with a 13 amp one.

Not sure what happens with a workshop but it seems that garages should have a specific type of consumer unit fitted. It will cope with one ring main for power. The rules on people tampering with ring mains but not sure that these include installing one. It's suggested that sums need to be done according to likely loadings. There are also statements about the maximum number of sockets but these assume that not all of them will be drawing 13 amps. Pop goes the fuse if too many do. I think that 2 used like this are ok providing nothing else is drawing current on an ordinary 2.5mm twin and earth ring main. Conduit runs do derate the cable though. Spurs need to be fused - 13 amps if 2.5mm and I am not at all sure that it's possible to increase this except there may be another method of wiring using heavier cable.

MK do a nice switched 3 way fused plug top that should be good for plugging bits and pieces in that don't draw a lot of power.

If there is a need to draw lots of power from the existing consumer unit it may need changing along with the main fuses. Some have 2 higher power outputs for an electric cooker and an electric shower. If this end is changed it's notifiable and has to be done by a qualified person and completely updated. Rcd's and earthing of water, gas pipes and anything else they want doing. It means upgrading to modern standards effectively. More connections to and older consumer unit doesn't seem to be a problem

A word of warning and why it's best to have some idea what can be done. We have 2 electricity meters. When one was changed to a smart meter because they couldn't get their head around us having 2 the bloke that did it phoned his gaffer to see if he could disconnect the one and link up the old style consumer units. He had what he needed in his van. 2 rather large barrier strip type things on steroids. His gaffer said no, extra work etc. The man doing the work told me to get onto them and tell them that we don't want to 2 meters etc. He warned me that when the people came who look at this sort of thing they would want to completely upgrade the electrics but that I didn't need to do that unless we wanted to upgrade the consumer unit to a single bigger one. They would do this because it's more work and profit for them and probably tell me that I must do this. Some electricians are much the same so if you run into one like this try another. One of our local chuches had a lot of work done in this area very recently and didn't want the whole lot upgraded due to cost. The electrician they used just found away of adding a lot without having to do this.

Not legal really but I recently thought for fun that if I wanted a more powerful plasma cutter I could fit a 25 amp socket to a normal ring main. It would be ok with nothing else on. Then I thought oh dear what about the 2.5hp plus compressor it would need. I use an unused cooker outlet for my garage. It was done a long time ago before idiots caused the changes in this area in terms of who can do what. Now there seems to be 2 types that can do work. Some all off it and some only in certain areas. Actually they are currently cheating by fitting a separate isolator so that ordinary electricians can work on consumer units. Well that's what the guy who did it told me. He was one of the ones that can do all. Also any type of gas work in his case.

John

-

 

Edited By Ajohnw on 19/12/2016 22:17:24

Dave C19/12/2016 22:32:44
101 forum posts
12 photos

Thanks John

The sockets have been wired as two separate radial circuits rather than a ring as I believe this is the best system from all the advice I have been given.

The consumer units have been viewed by an electrician and I have been told they are fine, One MCB and one RCD.

I was advised as to the relevant sizes for cables used as the welder I have is a 200amp unit. This can be used on a 13 amp plug but at reduced amperage and duty cycle and I want to have the full usage. I am having 16amp plugs installed for the welder.

As I say I have taken advice from electricians prior to carrying out any work and the completed installation will be checked and approved before any power is fed,

The additional breaker in the house is also on the advice of an electrician so that the garage has its own dedicated supply. Something I won't be going anywhere near as this needs a dedicated supply direct from the incoming mains. Hence my request for any local electricians looking for a little extra fill in job.

Many thanks for your long and helpful reply and rest assured nothing will be done without a full inspection. I am just trying as I say attempting to learn a little as the job progresses.

Many thanks

Dave

Emgee19/12/2016 22:37:13
2445 forum posts
291 photos
Posted by Ajohnw on 19/12/2016 22:13:36:

The method of wiring them is shown here

**LINK**

Hi Jon

I am sure you thought it helpful but why paste a link to a 2 way switched circuit when the question asked relates to 1 switch controlling 2 linked lights ? just confuses the OP.

Emgee

Ajohnw19/12/2016 23:22:25
3631 forum posts
160 photos
Posted by Emgee on 19/12/2016 22:37:13:
Posted by Ajohnw on 19/12/2016 22:13:36:

The method of wiring them is shown here

**LINK**

Hi Jon

I am sure you thought it helpful but why paste a link to a 2 way switched circuit when the question asked relates to 1 switch controlling 2 linked lights ? just confuses the OP.

Emgee

I read it as a two way set up as I can't see why a 2 gang switch would be a problem. Both need live feeds ect.  

But/Also

Generally the main wiring is done at the light so a single lead just goes to the switch.

Multiple lights on separate switches are  usual powered by a ring. Another reason why usually only a single wire goes to each switch.

There usually isn't enough room in the pattress to do much more.

John

-

Edited By Ajohnw on 19/12/2016 23:30:06

Emgee19/12/2016 23:47:43
2445 forum posts
291 photos

Hi John

The wiring Dave C describes is commonly used for outside lights to limit the number of wires at the outside light fitting and/or convenience of wiring. Any electrician would advise a 25mm deep patress if switching as described.

Lighting circuits are not wired as a ring circuit regardless of the number of switches or lights, they are all radial circuits.

Emgee

Speedy Builder520/12/2016 07:20:09
2653 forum posts
219 photos

Something I never understood, Why did/do the French switch the neutral and not the live?
BobH

mgnbuk20/12/2016 09:19:00
1207 forum posts
72 photos

Running supplies to outbuildings would appear to be Notifiable Work under Part P of the Building Regs.

It may well be that the electricians you have contacted are unwilling to get involved to complete & certify a project that they have not had full control over - the easiest way to get out of any involvement without being antagonistic being to say "too busy".

Nigel B

Dave C20/12/2016 09:57:07
101 forum posts
12 photos

All work carried out by myself is all surface mounted and clearly visible so everything is clear to see.the workshop is only small, So far I have had no difficulty getting electricians to do the work with the exception that all days I have been offered have been mid week and I work away from home. I have had difficulty getting people available when I am that is my only issue. All my work so far has been looked at and the response I have had is that what I have done so is fine.

I have only asked the question due to me having some time off over xmas. Unfortunately though everybody else also wants a break. I just wanted to progress the job a little further so I can finally power up my machine.

The workshop has planning permission and is all approved and as I say all electrical work will be certified once completed.

Dave

Ajohnw20/12/2016 10:10:15
3631 forum posts
160 photos

The other way you could do it a spur to each of the lights from the source in your workshop. Then 2 separate switch feeds for each light. The link I posted showed how lights are usually wired - the complex looking one where in that case all of the connections are in a standard ceiling rose. A piece of 5 amp barrier strip can be used instead. I believe there are some fancy push the wire in types as well now but personally I'd stick with screws. This way the only leads that go to the switches are the switch leads. The power connections are by / in the light.

If you do it the way you have then the live needs splitting to both switches. The live side of the lights connected to the other end of the switches and finally all neutrals linked up, earths too in the back box connector. Those must be sleeved. You may find that there isn't enough space in the back box or pattress to do this easily. You could use 2 sections of a 5 amp barrier strip to split live into 2 via 2 pieces of the insulated wire in the twin and earth. Then use the other one to link up the neutrals.

Also live could be split using the screw fixing on the switch. The live feed and a short piece of wire in one and the short piece going to the other switch. That's how rings are often done so should be ok but you still need to link up the neutrals.

John

-

Edited By Ajohnw on 20/12/2016 10:24:00

Russell Eberhardt20/12/2016 10:21:59
avatar
2751 forum posts
86 photos
Posted by Speedy Builder5 on 20/12/2016 07:20:09:

Something I never understood, Why did/do the French switch the neutral and not the live?
BobH

I've never come across that! Our house was built in 2003 and all switches at the distribution board are in the live as are all light switches.

Russell (in France)

V8Eng20/12/2016 10:23:40
1730 forum posts
6 photos
Posted by Dave C on 20/12/2016 09:57:07:

All work carried out by myself is all surface mounted and clearly visible so everything is clear to see.the workshop is only small, So far I have had no difficulty getting electricians to do the work with the exception that all days I have been offered have been mid week and I work away from home. I have had difficulty getting people available when I am that is my only issue. All my work so far has been looked at and the response I have had is that what I have done so is fine.

I have only asked the question due to me having some time off over xmas. Unfortunately though everybody else also wants a break. I just wanted to progress the job a little further so I can finally power up my machine.

The workshop has planning permission and is all approved and as I say all electrical work will be certified once completed.

Dave

I think you should read this and follow the relevant links on the pages.

**LINK**

Ajohnw20/12/2016 10:48:01
3631 forum posts
160 photos
Posted by V8Eng on 20/12/2016 10:23:40:
Posted by Dave C on 20/12/2016 09:57:07:

All work carried out by myself is all surface mounted and clearly visible so everything is clear to see.the workshop is only small, So far I have had no difficulty getting electricians to do the work with the exception that all days I have been offered have been mid week and I work away from home. I have had difficulty getting people available when I am that is my only issue. All my work so far has been looked at and the response I have had is that what I have done so is fine.

I have only asked the question due to me having some time off over xmas. Unfortunately though everybody else also wants a break. I just wanted to progress the job a little further so I can finally power up my machine.

The workshop has planning permission and is all approved and as I say all electrical work will be certified once completed.

Dave

I think you should read this and follow the relevant links on the pages.

**LINK**

Like lots of things on the web that isn't entirely correct. It would take a lot more typing to explain how the building regs aspects work out than what I mentioned earlier. There is another aspect to that as well. In some areas what was called the IEE make recommendations and that may add other things or differ in some respect. Those are generally met too.

It sounds like Dave is ok in respect to his consumer unit. When that is changed a full update is needed. Largely aimed at older houses that don't have rcd's.

Work can be certified too. Were things get complicated is when the direct mains is played with and there is no isolator. Odd really as the main fuses could be pulled instead. Also extending ring mains. Spurs are much less of a problem - a bit strange really if people think that through.

The direct mains aspect makes me laugh a little. It's caused problems as only certain people can do it. So they are fitting a totally separate isolator to feed the consumer unit. This avoids the need to pull the main fuses out which should be sealed. However there will be lot about with no seals. Done by ordinary electricians earlier.

John

-

Russ B20/12/2016 11:01:09
615 forum posts
26 photos

60 amps for welding! holy smoke, are you building the titanic in your garage!

My welder runs on a 10 amp fused extension quite hapily although it is only a baby welder!

Toby20/12/2016 11:48:30
117 forum posts
17 photos

My first post on this forum as I generally just lurk as I don't know what I am talking about! But electrics is something I do know something about (for my sins I was a registered electrician until recently) so I thought I would comment......

Given the other responses I think some clarification is worthwhile to avoid confusion.

So, as I understand it you have a two gang switch. One gang switching the internal light(s) and one switching the external lights?

If I understand you correctly, the internal light(s) are a standard two core switch line/return to one of the lights so it will simply be line (brown?) to the switch common and switch return (Blue?) to L1.

For the outside lights you have a Line & neutral supply to the switch and line and neutral out to the light(s)? If this is the case then follow Emgee's advice. There is no connection between the two switching gangs/circuits, just connect all neutrals (blue) together, the supply line (brown) to switch common and the light lines (browns) to the switch L1.

To avoid confusing (and perhaps be a bit pedantic!) I have referred to Line above rather than Live as strictly speaking the neutral is also a live conductor (and really can be "live" sometimes). Oh, and when I refer to the "common" of the switch, this is the one the other side from the L1/L2, so marked L in your case?

In case you don't already know this, all line conductors need to be brown, so if blue conductors are uses for switch returns (eg you internal lights) then need to be over-sleeved with brown at the switch and light. Also make sure you connect all the cpcs (circuit protective conductors or earths) together properly (with green/yellow sleeving). I am a big fan of wago push connectors for this sort of stuff.

eg: **LINK**

(although you might not find them worthwhile of you only need a few)

And (a pet hate of mine) don't do what used to be common practice, ie twist all the cpcs together and sleeve them overall. That makes it a pain to work on later. Just sleeve then individually and connect at the terminal block (or wago or whatever).

Also, a question, do you have any cables running over what might be considered an escape route? (ie the main door) If so they really should be supported by non-combustable means. These do not have to anything fancy, just an occasional metal strap would do. The aim is just to stop them sagging enough to catch you (or a fireman) if the cable clips melt.

A few other comments based on other responses so far:

Consumer units are no different in garages/workshops compared to a house. They all should be of a non-combustable (eg metal) material nowadays.

Yes, the work is notifiable, hopefully this is what Dave means by "certified" although strictly they are two different things. ie. the work needs testing and certifying, then notifying to building control.

As to the French switching the neutral, it is certainly against their regulations (as it is ours) but I gather they sometimes ignore it because, well, the French were never big on following regulations

A bit stupid really as it is the best way of killing someone, especially if you have multiple lights on a switched circuit (the neutral of the light fitting will be live even when "turned off" ) smile o

One last comment. This is obviously up to you Dave but I would recommend not energising and using any circuit until it has been tested properly. I know it is tempting to just wire it and use it but, even with the best will in the world, we all make mistakes and the proper test sequence is the only way of knowing it really is safe.

 

Lastly, you have my sympathy trying to get a electrician to help but I have to admit that I too would normally run a mile from the "I am wiring it myself can you just advise and certify it" type jobs. It is too easy for it to turn into a bit of a nightmare to get right and customers don't react well when you tell them it will be more expensive than doing it myself from scratch! On the other hand, customers that do the hard work (digging trenches, making good afterwards etc) are great

Unfortunately I am too far away or I would at least offer some more practical advice.

Sorry, that turned into a bit of a ramble, I hopes it helps...

Toby

Edited By Toby on 20/12/2016 11:49:28

Edited By Toby on 20/12/2016 11:49:47

Dave C20/12/2016 12:41:55
101 forum posts
12 photos

Thanks Toby

Yes you are understanding me perfectly about the light switch and thank you for your clarification. I was happy with the original explanation and it made sense to me but the comment about connecting the 2 gangs totally confused me.

Let me firstly get back to the beginning to explain my position. As previously stated I work away from home which makes things difficult. I was working in conjunction with the electrician who did the re wire on my house following my extension, therefore a new consumer unit etc etc all checked and approved, Due to this I am happy with that end of things. Due however to my work and the electrician also being extremely busy we agreed that all the donkey work would be done by myself, trench digging and cable running etc. All this has been done following instructions from the electrician and all cables are exposed with any connections made to sockets etc left open and exposed for checking. All materials have been bought as directed by the electrician and all was going to plan.

Unfortunately my electrician suffered a family tragedy recently which obviously turned his world upside down for a time which has left him in chaos. NOT HIS FAULT but this has left me in no mans land with a half finished installation, also not his fault however I now have two options, Try to carry on a little to minimise the work for somebody to complete or rip the lot out and get somebody in as a complete installation.

I have no intension of pressurising the guy as I would not wish to be in his position hence my post on here. I have however following all the replies on this site contacted his son this morning ( also a qualified electrician )

He has agreed to come on Christmas eve of all days to get my job completed, He is happy because his father is obviously fully aware of the job and also my situation. I will be having the work certified and fully tested on completion and I will either ask him or the council about notification of the work carried out.

Many thanks for all the assistance but fingers crossed and barring any further bad luck this issue is now resolved. Be on the look out for some CNC questions in the new year once I'm connected up.

Once again many thanks and all the best of the season to you all.

Dave C

Toby20/12/2016 13:17:15
117 forum posts
17 photos

Excellent, sounds you are sorted then.

Toby

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