What should I budget for getting a workshop wired up?

[Phil WhitleyParticipant @philwhitley94135]

Hi Bob Brown,

Re breaking seals on cut out fuses. We were told at tech college that this came under the Electricity supply act 1922/3 which states that if you arrive at an installation and find it in a dangerous condition you may remove the cutout fuse in order to make the installation safe. In a situation where the only alternative to working live is removing the cutout, I remove the cutout in order to make the installation "safe" to work on. I haven't been challenged by any supply authority in 40 years. I have on occasion informed the supply authority and asked them to come and reseal, never had a problem there either. The folks who bleat on about it being illegal, are generally less well trained or less experienced than they should be. Of course if the equipment wasn't sealed, it would be easier to nick the electricity, and harder to prove as there would be no seal to tamper with, and it is "tampering with the seals in order to abstract electricity" that is illegal.

Phil

[EmgeeParticipant @emgee]

Hi Joey T

The double pole earth leakage circuit breaker in your installation is voltage operated and not current operated.

For several years this type has not complied with the regulations, it can act as an isolator but only to the rating of 60A.

Emgee

[Phil WhitleyParticipant @philwhitley94135]

Hi Emgee

"For several years this type has not complied with the regulations",

This means nothing really, although you are correct to say it is voltage operated, not current. It complied with the regulations in force when it was fitted, if it is still in working order, that is all that is required of it. There is absolutely no requirement to bring installations up to compliance with modern regulations unless major works are undertaken or the equipment is faulty. There are still hundreds of thousands of this type of equipment in use, providing perfectly adequate protection provided they are tested by the householder (just like the RCD's are supposed to be). The IET will tell you that the more modern RCD's and MCB's provide better protection, but as I have said above, like this ELCB they do not fail safe, and therefore in the event of internal failure of the trip itself, the power stays on, and under the new system, there is no seperate fusing, only the cutout fuse at 60 to 100 amps. As an electrical engineer with over 40 years experience I do not consider this type of protection to be better, I find it to be much worse.

[CirclipParticipant @circlip]

Posted by Phil Whitley on 12/10/2014 12:03:47:

Hi Circlip/Ian.

Sorry, but that is a wind up on someones part,

Phil

Thanks Phil, Glad you have explained what didn't happen to ME on Christmas day in 1979. Wiring was less than five years old and DID go through a 5 amp wire fuse. "Chandelier" was a glossed up term for a single ceiling rose and wire to a standard single bayonet bulb holder.

Regards Ian.

[Phil WhitleyParticipant @philwhitley94135]

Hi Circlip,

I didnt say it didnt happen, what I was trying to expleain is that there is more to it than meets the eye, with wiring ony 5 years old that is even more worrying, thank the lord you are not there anymorre

Phil

[john fletcher 1Participant @johnfletcher1]

Regarding the blown 60 Watt lamp failing and then the main fuse blowing. Whilst this is not a common occurrence it does happen. As the element/filament fails it shorts across the pair of leads within the glass envelope forming a short circuit. The old type of wire mains fuse ages, not all premises have cartridge fuses even today. I will explain, the piece of wire, warms,expands, warms again, cools etc and gradually its cross connectional area reduces and then its fails, often at the most inconvenient time. When considering the size of cable for a workshop installation don't forget that you won't be using all machinery at the same time so total load is different to load in use. Diversity !

An interesting aside. 6 students rented a house, on arrival one switched on the hall light, it didn't work, another tried the living room it didn't work either. They tried them all of the lights and non worked, this was on a Saturday evening, so they used their phone to call the supply company. When the man arrive he checked the mains and all was well and at first he was a bit confused. The previous students had collected a lot of failed bulbs and fitted them to all lamp holders before departure. Total cost £75 .

[Nick_GParticipant @nick_g]

Posted by john fletcher 1 on 13/10/2014 15:26:54:

They tried them all of the lights and non worked, this was on a Saturday evening, so they used their phone to call the supply company. When the man arrive he checked the mains and all was well and at first he was a bit confused. The previous students had collected a lot of failed bulbs and fitted them to all lamp holders before departure. Total cost £75 .

This is what happens when parents buy their kids Nintendo consoles for Christmas and not Meccano.

Nick

[Phil WhitleyParticipant @philwhitley94135]

Interesting theory John, but I am very fa,iliar ith fuse fatigue, tht doesnt explain why the replacement fuse blew as well, unless it was also fatigued. Love te student tale!

Phil.

[EmgeeParticipant @emgee]

Hi Phil

With 40 years experience you should have identified the ELCB as a voltage operated type and not current operated.

Secondly if the installation had been converted to PME by the supply authority there would be a suitably sized earth conductor from the consumer unit connected to the neutral block, there is none showing in the picture.

I don't know any electrical contractors in my area who are prepared to install customer supplied materials for such a job, maybe where you are it is accepted.

Emgee

[Bob Brown 1Participant @bobbrown1]

I think the installation is a TT system with no supplier earth but an earth spike and an earth cable back to CU then on to the ELCB hence the single earth wire in the picture.

This system is common where the incoming cables are overhead.

As the garage is internal then it should not present any problems adding a sub main and I doubt the earth system will require any changes. If the garage was external then a separate earth spike would be required.

Not forgetting that cable sizes are now larger than they were in the past and that includes earth conductors.

Bob

[EmgeeParticipant @emgee]

Posted by Bob Brown 1 on 14/10/2014 08:03:20:

I think the installation is a TT system with no supplier earth but an earth spike and an earth cable back to CU then on to the ELCB hence the single earth wire in the picture.

Hi Bob

If this obsolete breaker has to remain then there needs to be 2 earth cables at the voELCB, 1 from the earth electrode (stake or spike if you want) connected to the E terminal on the breaker and the second conductor from the F (frame) terminal of the breaker to the CU earthing bar. This type of device responds to a voltage rise of up to 50v on the CU earth bar, it does not provide personal safety if the fault is from the live to metalwork not connected to the CU earth bar, a current operated device will provide personal safety as it is caused to operate by current imbalance between the live and neutral conductors, hence the availability of many different ratings and time delay types.

The best advice is to remove the ELCB and if no supplier earth is available fit a current operated device (RCCB). There are many types available but as it is possibly controlling all circuits at least a 100ma would be desirable, use a 30ma type for personal safety on selected final circuits as required.

Emgee

[JoeTParticipant @joet]

Posted by Bob Brown 1 on 14/10/2014 08:03:20:

I think the installation is a TT system with no supplier earth but an earth spike and an earth cable back to CU then on to the ELCB hence the single earth wire in the picture.

This system is common where the incoming cables are overhead.

As the garage is internal then it should not present any problems adding a sub main and I doubt the earth system will require any changes. If the garage was external then a separate earth spike would be required.

Not forgetting that cable sizes are now larger than they were in the past and that includes earth conductors.

Bob

I'm having a bit of trouble keeping up with the speed of this thread, but, yes Bob & Emgee, the property does have incoming overhead power cables.

[JoeTParticipant @joet]

Posted by Bob Brown 1 on 12/10/2014 13:08:35:

The Sparks should have no problem adding in a sub main after the meter/main fuse as they just need to remove the main fuse, there is a debate by some as to the legality of breaking the seals but most suppliers accept the need.

All sub mains need a fused isolator for the meter tails to connect into with the sub main from that.

Cable size and type for the sub main will depend on location of additional CU and if the cable runs external the it will need to be armoured cable, a 6mm SWA cable would be capable of 60 amps but length will reduce that figure.

For welders or large power connections I would be inclined to use a separate socket industrial 3 pin type something like these **LINK**

Bob

Cheers Bob – yes I was planning to use industrial connectors for the higher current supplies. The welding college has some sockets with a built in rotary switch that supposedly don't let you remove a live cable, or plug into the socket when it's 'on', but from the red colour on the plugs and the warning labels, I guess this might just be because they're 400V 3-phase. I will have a look for single phase 16/25A 230v ones.

[BaldricParticipant @baldric]

Posted by JoeT on 14/10/2014 13:15:36:

Cheers Bob – yes I was planning to use industrial connectors for the higher current supplies. The welding college has some sockets with a built in rotary switch that supposedly don't let you remove a live cable, or plug into the socket when it's 'on', but from the red colour on the plugs and the warning labels, I guess this might just be because they're 400V 3-phase. I will have a look for single phase 16/25A 230v ones.

Joe, I know those sockets and have seen them for 240v 16A with RCD so assume they are still available, the only issue I find with them is the number of people who can't get their equipment to work, the turning of the plug is not obvious.

Baldric

[JoeTParticipant @joet]

Posted by Baldric on 14/10/2014 13:51:16:

Posted by JoeT on 14/10/2014 13:15:36:

Cheers Bob – yes I was planning to use industrial connectors for the higher current supplies. The welding college has some sockets with a built in rotary switch that supposedly don't let you remove a live cable, or plug into the socket when it's 'on', but from the red colour on the plugs and the warning labels, I guess this might just be because they're 400V 3-phase. I will have a look for single phase 16/25A 230v ones.

Joe, I know those sockets and have seen them for 240v 16A with RCD so assume they are still available, the only issue I find with them is the number of people who can't get their equipment to work, the turning of the plug is not obvious.

Baldric

Hi Baldric – no, the ones I have in mind have a very obvious 50mm+ diameter round on/of switch – up for off, right for on IIRC. I have seen the ones with RCD's in them on the Screwfix site – I didn't realise that they had the issue with rotated plugs.

[SpurryParticipant @spurry]

You may want to look at the Gewiss range. I use the GW66015 and GW66004. The place at the top of a Google search seem very good.

Pete

[V8EngParticipant @v8eng]

The connector types mentioned here are probably the BS 4343 system, when I was working it was very common on industrial and site type applications.

I guess electrical wholesalers would stock it.

Edited By V8Eng on 14/10/2014 19:27:57

[JoeTParticipant @joet]

Posted by Spurry on 14/10/2014 19:06:20:

You may want to look at the Gewiss range. I use the GW66015 and GW66004. The place at the top of a Google search seem very good.

Pete

Thanks Pete – I think I've found the same things myself on Rapid Electronics' site.

[JoeTParticipant @joet]

I think I'm at about £500 in parts alone on my little spreadsheet which doesn't seem too bad to me.

Do you think it's reasonable to ask an electrician if I can put up all the conduit and source and place all the sockets where I want them on the walls and then just have them do the wiring? I don't really want to pay a sparky to do the cosmetic bits, and the layout is rather important if I'm going to be able to squeeze everything in.

I could probably do all the wiring myself apart from hooking the new supply up to the incoming mains, but I can fully understand why an electrician wouldn't want to certify wiring they hadn't done themselves, so I'm not going to ask for quotes for that.

Cheers,

Joe.

[Bob Brown 1Participant @bobbrown1]

I would be inclined to fit the conduit, run the cables, fit the sockets to the walls etc and let the sparks connect it all up including all outlets/switches then test/certify.

Bob

[JoeTParticipant @joet]

Posted by Bob Brown 1 on 17/10/2014 07:38:38:

I would be inclined to fit the conduit, run the cables, fit the sockets to the walls etc and let the sparks connect it all up including all outlets/switches then test/certify.

Bob

Yes, I will ask about that – I was thinking 2.5mm for the ring main and probably 10mm rather than 6 for the high current supplies – for a few more quid, I'd be able to plug in my welder into any of the high current sockets, rather than just one extra high current one.

Some people have suggested that a ring would allow the easy addition of extra sockets later – I can't visualise how that would work if you need to loop the cable through a new box though – I probably want to run my conduit above head level to keep the wall free for machines.

[Bob Brown 1Participant @bobbrown1]

If you are adding say 4/5 high power outlets there is nothing to say you can not run these as a ring main in say 6mm cable as apposed to 10mm as the load is fed from both ends of the ring.

Bob

[JoeTParticipant @joet]

Posted by Bob Brown 1 on 17/10/2014 11:07:46:

If you are adding say 4/5 high power outlets there is nothing to say you can not run these as a ring main in say 6mm cable as apposed to 10mm as the load is fed from both ends of the ring.

Bob

True, but I think I'd prefer to have the high power sockets on a breaker per socket so that I can isolate them individually.

[JoeTParticipant @joet]

Just a quick update – I've purchased 3 Geweiss GW 66015 sockets which seem really nice – good for 32A and interlocked so that you can't turn them on without a plug fitted, and can't remove the plug with the power on.

I have a couple of electricians coming over this evening to give me quotes – I will let you know how I get on!

Thanks for all the help and advice so far!

Cheers,

Joe.

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