Workshop electrics

[Dee J]

Perhaps we could get a qualified persons take on the difference in reality is between

1/ An “Electrically legally installed” spur socket in your garage/workshop with a 13amp fused 4 way trailing extension socket attached, which you then use for your equipment.


2/ Changing that same “Electrically legally installed” spur socket to a 13amp fused spur box, then running a radial from that containing 4/5 further sockets which you then use the same equipment.

Both examples have the opportunity to have the same overload situation.

Example 1/ would blow the fuse in the extension lead or possibly trip or fuse at the consumer box.
Example 2/ would blow the fuse in the spur box or possible trip or fuse at the consumer box.

I think everybody appreciates that a dedicated supply to the garage/workshop is necessary if you have heavy duty machinery or will run multiple machines at the same time.

[/size]

Both options would work. In both cases some overload protection is provided by the 13 A fuse. Most extension leads tend to be max 1.5 sq mm flex, whereas the radial would probably be in 2.5 sq mm (reducing volt drop).

The key difference is... is it a permanent or temporary setup. Chances are the extension lead will be removed and binned at some point, the radial may be there for 50 years (and used by others after your departure from the house or planet).

A comparable situation: You want an extra room on your house... option 1 you park a caravan on your drive... option 2 you build an extension - with all that doing so entails. Both give you a fix for your immediate requirement.

Dee

 

[MMUK]

Perhaps we could get a qualified persons take on the difference in reality is between

1/ An “Electrically legally installed” spur socket in your garage/workshop with a 13amp fused 4 way trailing extension socket attached, which you then use for your equipment.


2/ Changing that same “Electrically legally installed” spur socket to a 13amp fused spur box, then running a radial from that containing 4/5 further sockets which you then use the same equipment.

Both examples have the opportunity to have the same overload situation.

Example 1/ would blow the fuse in the extension lead or possibly trip or fuse at the consumer box.
Example 2/ would blow the fuse in the spur box or possible trip or fuse at the consumer box.

I think everybody appreciates that a dedicated supply to the garage/workshop is necessary if you have heavy duty machinery or will run multiple machines at the same time.

[/size]

Both options would work. In both cases some overload protection is provided by the 13 A fuse. Most extension leads tend to be max 1.5 sq mm flex, whereas the radial would probably be in 2.5 sq mm (reducing volt drop).

The key difference is... is it a permanent or temporary setup. Chances are the extension lead will be removed and binned at some point, the radial may be there for 50 years (and used by others after your departure from the house or planet).

A comparable situation: You want an extra room on your house... option 1 you park a caravan on your drive... option 2 you build an extension - with all that doing so entails. Both give you a fix for your immediate requirement.

Dee

Yes both would work but I for one, being 17th and all the additionals qualified, would never install and certify such a setup. Both are bad practise. Fine for a DIYer using very little in the way of leccy munching machines but it's always best to over-spec anything electrical, future proofing if you like.....

 

[Hemsby]

Perhaps we could get a qualified persons take on the difference in reality is between

1/ An “Electrically legally installed” spur socket in your garage/workshop with a 13amp fused 4 way trailing extension socket attached, which you then use for your equipment.


2/ Changing that same “Electrically legally installed” spur socket to a 13amp fused spur box, then running a radial from that containing 4/5 further sockets which you then use the same equipment.

Both examples have the opportunity to have the same overload situation.

Example 1/ would blow the fuse in the extension lead or possibly trip or fuse at the consumer box.
Example 2/ would blow the fuse in the spur box or possible trip or fuse at the consumer box.

I think everybody appreciates that a dedicated supply to the garage/workshop is necessary if you have heavy duty machinery or will run multiple machines at the same time.

[/size]

Both options would work. In both cases some overload protection is provided by the 13 A fuse. Most extension leads tend to be max 1.5 sq mm flex, whereas the radial would probably be in 2.5 sq mm (reducing volt drop).

The key difference is... is it a permanent or temporary setup. Chances are the extension lead will be removed and binned at some point, the radial may be there for 50 years (and used by others after your departure from the house or planet).

A comparable situation: You want an extra room on your house... option 1 you park a caravan on your drive... option 2 you build an extension - with all that doing so entails. Both give you a fix for your immediate requirement.

Dee

Yes both would work but I for one, being 17th and all the additionals qualified, would never install and certify such a setup. Both are bad practise. Fine for a DIYer using very little in the way of leccy munching machines but it's always best to over-spec anything electrical, future proofing if you like.....

We all have ways in which we prefere to do things, but are you saying that you would not certify this type of installation because you do not like it or because it is not safe?

 

[Dee J]

Properly installed, the 13A fused spur unit would be perfectly safe and adequate for a small home diy workshop running typical diy scale tools - one at a time. If you're trying to run larger semi-professional tools then a dedicated consumer unit and a properly planned system is the way to go. I would be happy to design, install and certify either variant, according to the need and budget of the customer.

Dee

 

[MMUK]

We all have ways in which we prefere to do things, but are you saying that you would not certify this type of installation because you do not like it or because it is not safe?

I'm not saying it is unsafe as such. I wouldn't certify it because there is a much greater potential for overload than with a dedicated ring main circuit.

In any case, before proceeding down this spur/radial route, you need to consider a) the existing circuit construction, and, b) what is on the existing circuit and the existing load potential. Even adding just a few amps to the existing circuit could overload it. In most cases I come across, garage sockets tend to be spurred from the kitchen or living room - both of these rooms can have high drain appliances on their circuits.

All I'm basically saying is exercise caution and make sure you're not going to load the circuit anywhere near it's limit. Bear in mind that a mains circuit can only carry up to 32A IF it is of ring construction, a radial circuit should have a maximum of a 20A MCB due to the load limitations of the cable.

 

[MMUK]

Properly installed, the 13A fused spur unit would be perfectly safe and adequate for a small home diy workshop running typical diy scale tools - one at a time. If you're trying to run larger semi-professional tools then a dedicated consumer unit and a properly planned system is the way to go. I would be happy to design, install and certify either variant, according to the need and budget of the customer.

Dee

Dee,

You are making the fatal mistake of assuming that the existing circuit from the board is a ring main. Even if the OP has had a new C/U fitted, there may still be radial circuits. See my post above.

 

[n0legs]

a radial circuit should have a maximum of a 20A MCB due to the load limitations of the cable.

Is a shower or cooker circuit not a radial circuit ( 32A 40A 45A 50A ) ??


I will make this point---
All of us in the know in a professional capacity have a duty that when giving, passing on, posting or implying any technical information that at the very least we are in the right when doing so.

n0legs out.

 

[Phil Pascoe]

Yes, but we're talking of a spur from a domestic ring main, not a shower supply. I think anyone following the thread would know that, if not MM's erred on the safe side.

 

[MMUK]

a radial circuit should have a maximum of a 20A MCB due to the load limitations of the cable.

Is a shower or cooker circuit not a radial circuit ( 32A 40A 45A 50A ) ??


I will make this point---
All of us in the know in a professional capacity have a duty that when giving, passing on, posting or implying any technical information that at the very least we are in the right when doing so.

n0legs out.

As just said, we're talking about a circuit that has normal 13A 3 pin sockets on it and 2.5mm cable, not a shower or cooker circuit :roll:

To wander slightly off topic, in either of those cases (shower or cooker) I install 10mm cable regardless of whether it needs it or not, the cost difference between 6mm and 10mm is negligible.

 

[n0legs]

Yes, but we're talking of a spur from a domestic ring main, not a shower supply. I think anyone following the thread would know that, if not MM's erred on the safe side.

Sorry Phil can't and won't agree. Read by the unintiated it is a bold statement for a public forum.
You are correct the talk is of a spur from a domestic ring circuit.
A radial circuit is a different entity and should have been explained as such.

 

[n0legs]

As just said, we're talking about a circuit that has normal 13A 3 pin sockets on it and 2.5mm cable, not a shower or cooker circuit :roll:

To wander slightly off topic, in either of those cases (shower or cooker) I install 10mm cable regardless of whether it needs it or not, the cost difference between 6mm and 10mm is negligible.

You were talking about 13A 3 pin socket circuits but you mentioned radial circuits.
Your statement , as I have pointed out to Phil in my last post, is a bold one. If you want to advise make sure your instructions are clear and concise. If you mention something validate it with an explanation.

 

[Woodchips2]

4: Ensure all legal and insurance aspects are covered.

That could be the most important issue of all.
If an installation looks 'dodgy' to a surveyor it could effect the saleability of your house and end up costing more than you save. The other, hopefully very unlikely, nightmare is that in the event of a fire a loss adjuster won't like any illegal installations and make deductions, or worse, fail to make any settlement.

One of the legal questions you'll get asked if you need to sell the house is "Have any alterations been made to the electrical installation? If so please detail the works and provide a copy of the certification". So even if you do the works yourself you will still need to get it certified so I suggest you discuss the installation with the certifier before doing the work to see if he is happy with the proposal.

It's not just electrical work you'll be asked for certificates if you sell the property, it applies to central heating and double glazing so keep all those bits of paper safely (hammer)

Regards Keith

ps My son had halogen down-lighters installed in his bathroom by a qualified electrician. One was faulty which caused a major fire in the roof and the cost of repairs exceeded £100,000. He had the certification otherwise the insurance company would have turned down the claim.

 

[n0legs]

I will make the point that anything in this post or in any of my previous posts are not a personal attack upon anyone.

I am in my 29th year of my career in electricity and I feel I am well within my rights to comment and hold opinion on electrical matters.
In these 29 years I have lost 3 friends due to electrical accidents, I will name these people.
Brian Doble
Bert Wilcox
Bob Smith
They may be mentioned somewhere on this internet universe if others wish to search for them.

My point, well lets get to it, all three were extremely well trained, experienced and technically able craftsmen. Brian and Bert both died due to poorly conveyed information/instructions. Bob died due to an extreme bit of bad luck, but still a death caused by electricity. Deaths that I cannot forget and deaths that shaped the way in which I have learned ( the hard way ) how dangerous electricity can be. The same can be said for information, lets not forget "a little knowledge, etc, etc, etc".
I suffered an electrical accident in 1991 that left me blind for a fortnight and having to have 2 operatons to remove embedded aluminium from both eyes. How did my accident happen ? Bad information and on my part poor understanding.

If we feel we are going to advise people on electrical matters and issues lets look at some facts first.
Who are we informing/telling.
What is their understanding of electricty and technical ability.
Will they follow to the "T" the information we provide them with.
Is our own understanding of their issue clear and is our information we are passing on correct.

As a craftsman I like may others enjoy being asked to comment or tell tales of my trade and waffle on for hours, it's a form of flattery to be asked "how do you do that then". Lets face it we all like to think we know or have great ( and greater ) knowledge ( than others ), also it's good to be able to help out others. But.....
There is a reason that we have the IEE Regs, Part P and trade qualifications. The reason is to ensure that only competent people carry out the works.
I have said for years that the electricity industry should be regulated the same way as the gas industry. At least you can hear and smell a gas leak.
This is in no way a way of us "sparks" feathering our nests or to make us thousands, it is to make sure homes, public buildings, work places, etc are safe for the people who occupy them. I do not wish to insult anyone here, I'm sure there are many very talented people who could carry out electrical work to a high and safe standard, but full and clear understanding of electricity is a must.
I used to find it absurd that a diyer could go to his local library get a book on home electrics and then carry out a rewire on his own home.
I once investigated a fault where a diyer had managed to get wrong polarity on the whole of the household installation. That was really a WTF moment !!!

I urge extreme caution in advising anyone about electrical matters.
I urge extreme caution for those seeking advice, I will go as far to say that if you are looking for guidance for electrical works on a public forum then in my honest opinion you should not be carrying out the works in the first place. Harsh yes, but is it true ?
I like some others here have the benefit of an apprenticeship and formal electrical training, I have no doubt that there are some very highly qualified persons here, however some of the advice given here does cause me concern.
I, as I stated in a post some months back, could advise on many electrical matters and works but choose not to due to my concerns about how the information I provide could be used. You reading this may think this is somewhat petty, but I make no apologies for it.

This is a long winded post and I accept that some may feel it could be overbearing, but I hope that most of you who read this will realise that this has been written and posted in an effort to keep people safe

I've said my piece and I hope that those who truly are qualified to work with electricity will agree with some of my points. Those of you who are not then my best advice for you is to tread carefully, where there's blame there's a claim.

 

[Rhossydd]

I've said my piece and I hope that those who truly are qualified to work with electricity will agree with some of my points. Those of you who are not then my best advice for you is to tread carefully, where there's blame there's a claim.

Well said.
It might also be noted that giving bad advice that leads to an injury claim might make the advisor liable themselves, I wouldn't want to be a test case.

 

[Dee J]

Properly installed, the 13A fused spur unit would be perfectly safe and adequate for a small home diy workshop running typical diy scale tools - one at a time. If you're trying to run larger semi-professional tools then a dedicated consumer unit and a properly planned system is the way to go. I would be happy to design, install and certify either variant, according to the need and budget of the customer.

Dee

Dee,

You are making the fatal mistake of assuming that the existing circuit from the board is a ring main. Even if the OP has had a new C/U fitted, there may still be radial circuits. See my post above.

I'm not making any assumptions here. If installing the fused spur , or indeed any modification or extension to an existing system, I would first inspect and test the existing installation to ensure it was safe and appropriate to do so. I've seen enough weird, mis-wired and downright dangerous setups - assume nothing.

As I said in an earlier post...
The main reasons for employing an electrician:
1: Interpret how the existing installation is configured.
2: Test that installation to ensure it is functioning correctly.
3: Design and implement any extension or alteration to that installation to ensure safe legal functioning.
4: Ensure all legal and insurance aspects are covered.
The grunt work of cable chasing and connecting up the bits is just the visible part of the iceberg.

If you can't complete all 4 items on the list then don't start.

Dee