Garage Power in new Property Complete Reworking


Postby greengrass » Wed Aug 09, 2017 2:48 pm

I am competent having done a complete lights job, jb;s etc on lighting in our London house and it passed with flying colours, before the new regs.

We moved to the coast and the garage Elecs need to be re-done its a mess of cables. I want main cable at ceiling level our of the way, with drops to sockets from Junction boxes.

I want to run new as a radial 2.5 cable for 4 sockets 13amp. max load would be on occasions Ryobi table saw at 6.5amp (1500w but open to corrections). 3 sockets will be tool sockets at various position in the 32ft garage to work with occasional power both ends of garage without extension leads trailing. The remaining socket to run two freezers.
Lighting will be 3 maybe 4 3 ft strip lights. The power will of course be disconnected at the incoming point from bungalow. An external armoured cable found in garage will be to feed the Wickes C.U RCB type
One thing I do know is Electric current takes no prisoners so safety is paramount. Praise or tear to pieces If you want. Sockets drop from JB
It will all be checked, checked again then double checked before switching on.
Many thanks for your read time and responses.
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Postby kbrownie » Wed Aug 09, 2017 6:09 pm

Why use junction boxes?
Checked, double checked and checked again, using what method?
and who will be completing the required documentation?
Your table saw will likely have an inrush current at start up.
In what way did your previous work pass with flying colours?

With what you have said, I find it hard to believe you really are competent enough to carry out electrical work safely.
Sorry if this sound harsh.
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Postby Mr White » Wed Aug 09, 2017 7:04 pm

I too do not want to "rain on your parade" but you have shown your incompetency by showing your lack of understanding of the job in hand. I know this is a DIY forum and we all try to help, but as you yourself said "Electric current takes no prisoners so safety is paramount." on that note, I suggest you get an electrician in to do the job for you.
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Postby BLAKEY1963 » Thu Aug 10, 2017 11:22 am

Greengrass

I appreciate you would like to undertake the work yourself.
The inspection,testing and certification side of the work required
needs to be considered, and a competent persons scheme registered electrician , should be consulted to help you with your plan of works
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Postby ericmark » Thu Aug 10, 2017 7:05 pm

BS7671:1992 is I suppose when the regulations became widely know, it was at that point where people started to go to collage and take exams to show they had read them, it was the first reprint of the 16th Edition of the regulations and has since had many upgrades the two major ones being BS7671:2001 and BS7671:2008.

In those 25 years there have been many changes, in 1991 we had earths on lights, then we had the move to MCB’s rather than fuses meaning the earth loop impedance became much more important, the old ELCB-v has been outlawed and the RCD now is used for circuit protection on most circuits.

Volt drop allowance has been modified in those years, but the two major items which suffer when there is volt drop is the fluorescent lamp and refrigeration units. And you have both. Typically a freezer takes less than ½ an amp running, but a massive 10 amp to start, and it is the starting which causes the problem, they have an overload so should they try to start before the pressure has dropped then it will trip and reset it is hoped after the pressure has dropped, with a volt drop it can try restarting many times and can burn out the overload as a result.

2.5 mm² cable will carry 10 amp for around 70 meters before the volt drop limit is reached, so there should not be a problem, however raise it to 13 amp and it drops to 53 meters, 16 amp down to 42 meters, and at 20 amp down to 32 meters, it would seem your well within the limits, however this is from the consumer unit including any cable joining garage to house.

When ever is see the statement “I am competent” it rings alarm bells, the classification was dropped with amendment 3, but there were four classes of person, starting with ordinary, then instructed, then skilled, the highest was competent and I will admit the difference did not seem to make sense, skilled person can look after his own safety and competent can also look after the safety of others. A competent person is NOT the same as being a member of a competent persons scheme, maybe that is why the classification was dropped to avoid confusion.

There are as well as the regulations also laws, the laws vary area to area the health and safety at work act is nation wide, but Part P in England is different to Part P in Wales.

In the main outbuildings will drop into two types, the simple fuse connection unit (FCU) feeding the building with a second switched FCU with smaller fuse for lights, or the MCB/RCBO in main consumer unit feeding a sub consumer unit in the out building which in turn has an array of MCB/RCBO protected circuits. It would seem the former even though BS7671 would describe it as forming new circuits Part P building regulations don’t, although I have not seen any official document to say that. However once you use a consumer unit, then it will be seen as forming new circuits. So it seems very likely that the work is notifiable.

There are two or three methods depending where you live, either pay the local authority a fee, or pay a third party a fee (England only), or use a scheme member electrician. The latter is likely the cheapest.

The problem with all DIY work is 99 times out of 100 nothing alerts the authorities anything untoward has been done, so we get away with it. When it does go wrong however then the questions are asked. It seems daft in this country I can buy things which I can’t legally use, for example a ham radio can only be used by a licensed radio ham, but anyone can buy one, walk into the DIY sheds and they are full of things you are unlikely to be able to legally use, the regulations on wood burning stoves for example makes it very hard to actually fit and use one within what is allowed by law. However the DIY sheds still sell consumer units and the like to the general public.

There are surprisingly very few domestic deaths due to contact with electricity, although likely many more due to fire caused by the electrical items in a house, when it does happen then it seems the courts hand out really high sentences, often it seems not to the person one would expect to be held responsible.

Law has some odd rules it seems, but I have always said I don’t want to be in the firing line when case law is laid down even if found not guilty, these cases seem to take up to 10 years for the result to be declared.

I feel in my house I should be allowed to do anything which will not endanger others, however other people do visit my house in an official capacity, from post man to gas man even the double glazing salesman my house is his place of work, so the EAW act applies.

As to drops for each socket yes I have done that both to reduce the loop impedance and to remove as much wiring as I can out of harms way, but when you sign the installation certificate you need to be able to say why you have done it, you sign to say you have the skill to design, install and inspect and test. It is no good saying well I asked on a forum.

People seem to think they can do electrical work then get it tested, it does not work like that, every part has to be agreed, so when I took over my mothers wet room job, first thing was contact the council, when I state what I intend to do, they then say yes or no, and if yes they will say when they want to inspect, surface wiring likely at the end, but it is up to them not you.

They wanted to see my test equipment some £400 worth, and wanted to verify I had the skill, both my son and I are both electricians, however they would not accept his signature it had to be mine, as I had a degree he at that time did not.

I don’t like saying don’t DIY, however I think you need to understand what your letting yourself in for. I think the LABC Part P thing where is says you can DIY is really for non scheme member electricians to work on their own home. Not for normal DIY men.
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Postby greengrass » Sat Aug 12, 2017 12:44 pm

Post to all who responded.
Thank you.
Shot down in flames especially ericmark he had most ammunition.
The house remark the inspection was by supply electrocution who replace the fuse lead seal on incoming cable at same time checking what I had done.

As for garage may leave it as it is have had no problems with it. It's just a "tidy" trait of mine so will box all cables instead.

Only two problems since 2004 when we moved in both the strip light starters failed.
And all said the garage tested by electrician friend who was certified working for Insurance company testing places like Petrol refineries etc.
Well the comments have deflated my ego for......wait for it!..............my own ignorance and safety of modern electrics
and do's, don't and cannot.
However, Am I correct in saying I can replacing an existing socket, light or cable without notification or follow up testing?
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Postby ericmark » Sat Aug 12, 2017 10:56 pm

The BS7671 regulations say you should always test, however there is not much you can get wrong replacing a socket, so not really that much of a problem. Of course if tight wires then you should test in case one has popped out, easy for an electrician, before starting I plug in my loop impedance meter and record the ELI and PSCC then when swapping I test the ring is intact, and one replacing again measure ELI and PSCC. Should a wire pop out, then the reading will show it.

However for the DIY man without a loop impedance meter, he would need to remove the cover from the consumer unit to test wires, here we have the problem, he could one touch live wires while testing, and two disturb something which creates a worst fault than would have existed had he left well alone.

So although you should test, in real terms likely better if your just careful and do things like tugging at each wire to ensure well clamped, and use some common sense.

As to notifying it depends where you live, England new circuits, bathroom and consumer unit changes. Wales also kitchens and gardens, in fact in Wales easier to say what doesn't need notifying rather than what does.

I have just has a electrician employed by local council move a light fitting and not issue any paperwork, theory since I did not order the work, he does not need to issue me with paper work, only has to give to council. I am sure he has never raised any, and when I renewed standard sockets for USB type I did not test. Mainly as my son has my tester.

But use common sense, the whole reason for the 10 years installation condition report think 2 years in Scotland? is to find any errors you have made doing DIY. Wire does not really ware out.
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Postby kbrownie » Sun Aug 13, 2017 7:42 am

Replacing sockets, lights and damaged cables does not require notification.
With regards to testing, it is always wise to test the part of the installation are working on prior to undertaking work and then again after.

I say this, as there maybe a historical fault on the circuit, that needs attention before any other work can proceed.
If this is not spotted before you do change sockets etc.. When you hen test, you likely will not know if you have introduced a fault or if there was already one present. Which can be a little frustrating, if you keep checking your work and it is something historical.

Also when changing plates, terminals need correct polarity and earthing, This needs to be checked, also you could quite easily snag a cable, so IR testing would be needed as would Zs
Replacing cable the same applies, polarity, continuity, r1+r2, IR and Zs are all things needed to prove safety..
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Postby greengrass » Sun Aug 13, 2017 10:09 pm

Thanks again to all,
I will only change a couple of socket positions. and box in the cables.

I all ways tug hard on wires after wiring up

The circuit was tested in garage as ok by Electrician friend fully qualified to do so, unfortunately no longer with us, testing for 'Him up stairs'.

Any work I do the power will be off at source. the two freezers kept running from extension out of the bungalow.
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Postby kbrownie » Tue Aug 15, 2017 6:40 am

You still need to conform to BS7671 and Part P.
These would include correct selection of cable, routing cables in the prescribed safe zones, inspection, test and certification.
If this is beyond your scope and your previous electrician is unfortunately no longer with us. I suggest you employ another electrician, or you could also be doing your DIYing for him upstairs.
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