Help me before the sparks start to fly...

[Wood Monkey]

I know electricity doesn’t suffer fools, but I’m starting to wonder if being electrocuted may be the less painful.

I’m approaching the final stages of constructing my workshop and it’s electrical installation time. I’m pretty much there with respect to specification and layout. Basic overview.

6.0mm 3 core SWA from spare slot on my house CU (35 meters).
Terminating on 5 way CU with RCD in the workshop.
Breaker for lighting. 4x5ft twin strip lamps, plus 1 bulkhead lamp outside the door.
Breaker for power ring. 6 x twin sockets plus 3 x single sockets
Breaker for separate circuit for 3 16A sockets strategically placed for future proofing.

The building is shiplap cladding over a moisture barrier on 4x2 bearers with ply roof on 5x2 bearers. The walls are all clad in 12mm ext ply with insulation in the cavity and the whole thing stands on a single course of bricks on a concrete base. The intention was to run 2.5mm conduit cable in surface mount 20mm steel conduit all of which has been sourced from a ‘job overrun’ FOC (my kind of price). The only variation on this is to run the lighting cable in the ceiling void, which will be filled with insulation, and then clad the ceiling with T&G pine boards.

I was ready to go (I’d actually started) when I started to get stuck into the 16th edition and Part P. Now I’m completely stuck regarding what is allowed and what isn’t.

1. Am I allowed to install the cable in the ceiling void? Part P talks about Rodent attack, but doesn’t tell you what is deemed suitable as protection.
2. Do I really have to bury my SWA at least 450mm or go ‘overhead’? I wanted to follow the fence line, but getting to it and digging an 18in deep trench is not doable. I was going to run the SWA in steel galvanised conduit suspended on dedicated posts along the fence line. Can I?
3. My local authority guidelines are useless, and seem to suggest I have to leave all the installation exposed to allow inspection. Is this true?
4. I’m supposed to tell them before I start installation, but they can’t tell me when I will be permitted to start.
5. They say they outsource the inspections, but can’t tell me how much their inspection will cost until it’s done (despite Part P mentioning that the cost of building control inspection should not be passed on to the home owner).
6. Legally, does this only become an issue when I sell the house? If so, can I just disconnect it if I sell? Can I get retrospective approval?
7. Is there implications with my house insurance in the event the worst happens?

I know Part P is there to protect us but I want to do my own installation, partly for cost and partly for pride, and Part P seems to make this close to impossible.

Who’s been there and done it? Is it really that bad?

Please help.
Jon

 

[mel]

cant help with most of the problems you have, sorry
if i was running a new cable to my workshop again it would definitley be a 10mm armoured , about the same run as yours . 35metres
someone will help you im sure
im not an electrician
mel

 

[davy_owen_88]

I'm not fully up on all the regs - so I would hate to give you wrong info but heres my take on the situation:

The regs do state that you should avoid running cables on known rodent routes and if you have to to use steel conduit for protection.

Attaching the cable to a fence is risky... what if the fence blows over in high winds? Even if they are dedicated posts a fence hitting them might just be enough to loosen a connection. Maybe leaving plenty of slack is an option but I think its best to go overhead or underground, and if you are going underground make sure it is to the stated depth and is clearly marked with tape.

Regarding the cable, heres a good calculator to determine the cable size you need. Just work out the maximum power draw you expect to need (so the most powerful machine with the extractor running and lights and maybe a heater for example) then just plug the numbers in.

I would just go for 10mm if the cost isn't too high though to allow for future expansion.

 

[bobscarle]

Jon

I recently put power into my shed. I ran a 10mm SWA from the main Consumer unit to a new one in the shed. I dug a trench about 300mm deep for the cable as the only guide I could find was something along the lines of "Reasonable Depth". I provided all the wiring inside the shed, ring and lighting. As for running the cable along a fence, I don't think it is a good idea.

I paid for an electrician to come out. He provided a new consumer unit in the meter box (the other was full) and a new consumer unit in the shed. He tested all of my sockets and all of the lighting circuits. He then made the connections. The charge for this was £350.

My wiring checked out OK. I ran the lighting cable along the roof trusses and told the electrician that I intended to clad it. I also left the trench open for inspection, although I do not belive he looked at it.

I was told there is no need to inform the council before starting work, they are informed when the certificate is issued.

So why pay £350 when I could have bought wood and tools? I did not want to run the risk of an insurance company wriggling out of a claim if they suspected faulty wiring. I needed to know that the wiring was safe (I regard my self as competent but I am not an electrician) and suitable for the purpose. I am not sure of the legality of disconnecting before you sell.

That was my experience. I have no way of knowing if that is typical or not but I hope it helps in some way.

Bob

 

[OLD]

My experience of the council is they very rarely have a application from a non competent person so do not no what to do ,but any electrical testing is contained in there fee.It could be dealt with on a cost basis is it cheaper to get a electrician to check test and connect or pay the council to do the same.
The regulations look complex but just require good electrical practice and protection by a rcd as its a external area and say a mower which can cut its cord and kill you could be connected to your installation.
If you go with the council after paying the fee you get a letter saying don't start, just ring up have a chat and agree to start they will be helpful.
My opinion is running the swa along the fence is ok wiring for lights do as you would run cables in stud work.when all is completed inspected/tested you get a letter saying all work complies with regs keep with house papers job done.
My inspection was daft just a walk round and a brew no electrical testing.

 

[PowerTool]

Did all my own wiring,but got it all done within the transitional period with Part P,so never had to involve BCO or an electrician.
My SWA is buried about 450mm,and under concrete - recommended depth is apparently 750 mm if in "open" soil.Can be clipped to a stable structure (although I also don't like the idea of clipping it to a fence) or can go overhead on a catenary wire,which if I remember correctly,is recommended to be 3 metres high.

Good luck with it all.

Andrew

 

[RogerS]

I won't comment on Part P.

My one suggestion relates to you only proposing ONE way in the CU to run up to 3 16Amp circuits (if I understand you correctly). My understanding was that best practice was ONE MCB per circuit and rated at 16Amp. Which means that you need three separate ways in the CU for your three 16A circuits.

You also make no mention of any RCB's anywhere but I'm guessing that this is an oversight?

OK..OK..I know...if we're working by ourselves we'll only have one piece of kit running at any one time........

You might want to run the power cable through a length of drain pipe plus a pull through 'to future proof'. I would have thought that the drainpipe would also give you additional mechanical protection to minimise the need of digging the Mariana trench in your garden.

 

[Wood Monkey]

Thanks for the advice guys. To clear up a few points.

My intention is to have an RCD on the workshop CU and my assumption was that this would be sufficient.

10mm.. Good point may as well (although the cost is quite a bit more).

The SWA run will not be attached to the fence. The fence that is there is only a picket fence, so my intention was to put dedicated posts in. To bury the cable among the mature shrubs would be impossible and overhead would not be inkeeping with the surrounding and would likely upset a few people.

I have 5 way CU, so seperate breaker for each commando is possible. I was assuming all three on the one breaker on the basis I would only use one at a time. Thanks for noting this.

Let the struggle go on.....

 

[OllyK]

I'm not condoning the following, but it is worth pointing out that the new wire colourings (brown and blue from red and black) came out before Part P came in to force. You therefore can't tell from the look of the wires if it was installed before or after the new regs. Assuming that you didn't need planning permission for the shed you have built then you "could" claim the work was done prior to part P.

My cable to the garage / workshop is 50m run of armour, 1m deep in conduit, but then my sparky is one for overkill!

 

[Anonymous]

Are you sure that the 6.0mm will be adequate?

In the latest regs, the voltage drop per meter for 6.0mm is 8.4mV/m, so for your 35m, the voltage drop is 7.056V for 20A flowing if the cable is buried (with buried cable, there is a multiplication factor of 1.2 due to higher temperatures in the cores)

Well, the maximum permissible volt drop is 4% of nominal voltage (240V) which is 9.6V

So, for maximum of 32A consumer unit with 32A flowing, lights, fan heater,dust extraction, kettle and big power tool, radio etc.

The volt drop is 11.23V - above maximum permissible.

For 10mm cable, the volt drop per m is 5.0mV/m, giving 6.72V for 32A.

Use 10mm cable. Bury it, don't string it across posts. Consider an RCD at the feed end to protect anyone digging.

 

[Adam]

2. Do I really have to bury my SWA at least 450mm or go ‘overhead’? I wanted to follow the fence line, but getting to it and digging an 18in deep trench is not doable. I was going to run the SWA in steel galvanised conduit suspended on dedicated posts along the fence line. Can I?

I just buried mine at 450mm (I hired a trench cutter from HSS for the day, like you it was about 35m). The problem with fences is they are not considered "permanent" installations.

3. My local authority guidelines are useless, and seem to suggest I have to leave all the installation exposed to allow inspection. Is this true?

They did come and inspect my trench, although I agree, they weren't quite sure if they did or didn't need to, so in the end, (as it really was that depth) they came out. When they got here mind, they couldn't tell me that 450mm was the right depth, I have to tell them, and they had to go look it up.

4. I’m supposed to tell them before I start installation, but they can’t tell me when I will be permitted to start.

Normally, you have to provide 24 hours after submission of your intention to start work

5. They say they outsource the inspections, but can’t tell me how much their inspection will cost until it’s done (despite Part P mentioning that the cost of building control inspection should not be passed on to the home owner).

The full cost of test is shouldered by the local authority, the regulations that allow them to pass that cost on have not been implemented. You only pay the cost the building control application (£110 where I am). I had to argue, and prove that it was not me that paid the "testing fees" and in the end, they backed down. Send me a PM for more info, the website for the department of the deputy prime minister has all the info. They cannot charge you for the testing. Only the standard Building Control fee.

6. Legally, does this only become an issue when I sell the house? If so, can I just disconnect it if I sell? Can I get retrospective approval?

Better to get it now.

7. Is there implications with my house insurance in the event the worst happens?

Normally, provided you are a DIY incompetant, insurance companies pay out. If you are a professional working on your own house, it gets to a grey area.

I know Part P is there to protect us but I want to do my own installation, partly for cost and partly for pride, and Part P seems to make this close to impossible.

Who’s been there and done it? Is it really that bad?

Please help.
Jon

No, its fine. Notify the council, pay the appropriate fee (around £100 in my area). Do the wiring to BS7671, remember the new wiring colours, don't try and mix colours, call the council when you are finished, they send an ellecy to test and sign off, and issue you the part P certificate. Its that simple. For me, I'm the first person ever in my local authority to do this - and they don't have any "commissioned" electricians, and the big cheese in the council hasn't approved one yet. So they have (privately) asked for 1 weeks notice, as, in normal cases, provided I ring before 10am, they should come out and sign off the same day. But I thought I'd be nice to them! Of course, any problems at the inspection, you still don't have to pay for any re-visits no matter how many. You've paid your BC fee and its a flat rate.

Adam

 

[Wood Monkey]

I just had an unbelievable conversation with the Chief Building Officer.

It will cost me £200 to submit a ‘Building Notice’ and this doesn’t cover the cost of the test/inspection. Once the work is complete, they will ‘employ’ and qualified leccy to perform the testing and provide the compliance sign-off, then the charge will be passed on to me. I explained that my understanding was that the cost of testing should be included in the building notice fee (I quoted the department of the deputy prime minister) and he explained that the council members had decided that the council shouldn’t subsidise these inspections under Part P. His tone suggested I shouldn’t attempt to argue.

He also said I needed to be registered as a competent person if I want to do the work myself, so the DIY option is a non starter in our borough. I guess it could be inferred as if you wanna do it yourself, don’t tell us.

The council in question do not provide a list of approve leccies because, “the borough is awash with bogus electricians and the council do not want to be drawn in to the implications of recommending someone who turns out to be a fake”. He simply pointed me to the list of contacts for the authorities who are responsible for Part P and the ‘Competent Persons Schemes’.

He turned out to be a very straight up guy who offered me a lot of off the record advice which has left me with a clear plan of action. It was clear from his comments, such as “I’m a bricks and mortar building surveyor and then someone decides I’m now responsible for electrical safety. What do I know about electrical safety?” and “If my department worried about every person in the borough who wanted a light in his shed, we’d never get the job done. We have bigger fish to fry”.

I take my hat off to him. He pointed me towards a flexible leccy who will be happy to work with me so I can still do the bits I want to do but still make sure I’m safe and complient. It was clear to me that the Chief Building Officer doesn’t agree with the way Part-P has been implemented, but if he can’t beat the system, then I shouldn’t waste my time trying either?

An electrician is lined up and I’m resigned to spending some of the cash I has set aside for tool upgrades, Hay Ho… Thanks for all the responses, I’ll share details of the final install for anyone who runs into similar problems.

 

[Adam]

He also said I needed to be registered as a competent person if I want to do the work myself, so the DIY option is a non starter in our borough. I guess it could be inferred as if you wanna do it yourself, don’t tell us.

Absolute Rubbish. I'll dig out the quotes. Give me a few minutes....http://www.communities.gov.uk/index.asp?id=1131042

How about this?

There have been reports that some local authorities are asking householders to have electrical installation work inspected, tested and certificated by someone other than the person carrying out the work. Section 33(2) of the Building Act 1984 (which would give power to local authorities to require persons carrying out building work to carry out such reasonable tests, at the person's expense, of or in connection with the work for the purpose of enabling local authorities to ascertain whether the work complies with the requirements of the Regulations) has not been commenced. This means in our opinion that local authorities do not have the power to require householders to retain an electrician to test and certificate the work in accordance with BS 7671. Local authorities which have adopted such a practice should discontinue it immediately.

??

And that it is a fixed fee? See here:

Local authorities should ensure that charges for checking full plans applications or building notices and carrying out inspections of building work, including that relating to Part P, are pre-fixed in their charges scheme as required by the Building (Local Authority Charges) Regulations 1998. Authorities do not have powers to reassess a fixed charge, which they have levied for a particular application or notice, during the course of the work.

And I have an email from the Buildings division, (department for comunities and local government) when I double checked it was OK for me (as a non qualified person) to do the work and they said...

I am afaraid that your local authority may have misinformed you. Part P of the Building Regulations places no restriction who may carry out electrical installation work in dwellings.

and also...

Please note that local authorities have no powers to require you to have the work inspected and tested at yopur expense. If it requires that this needs to be done it must be at its expense.

I suggest that you may wish to draw to the local authority's attention the relevant paragraphs in the Approved Document.

I've got a copy of the attached document, and it notes:

Where installers are not qualified to
complete BS 7671 completion certificates
1.24 Where such installers (who may be
contractors or DIVers) carry out notifiable electrical
work, the building control body must be notified
before, the work starts. Where the work is
necessary because of an emergency the building
control body should be notified as soon as possible.
The blJilding control body then becomes
responsible for making sure that the work is safe
and complies with all relevant requirements in
the Building Regulations.
1.25 The amount of inspection and testing
needed is for the building control body to decide,
basecl on the nature and extent of the electrical
work. For relat,vely simple notifiable jobs, such
as ad jing a socket-outlet to a kitchen circuit,
the inspection and testing requirements will be
minirral. For a house re-wire, a full set of inspections
and tests may need to be carried out.
1.26 The building control body may choose to
carry out the inspection and testing itself, or to
contract out some or all of the work to a specialist
body which will then carry out the work on its
behalf. Building control bodies will carry out the
nece~)sary inspection and testing at their
expense, not at the householders' expense.

I'm sorry, but your building inspector is talking absolute utter rubbish. Possibly, like my local authority they are trying to wriggle, but I stitched them up with the confirmations above. After forwarding those documents on, they fell into line. :shock:

Adam

 

[Adam]

He also said I needed to be registered as a competent person if I want to do the work myself, so the DIY option is a non starter in our borough. I guess it could be inferred as if you wanna do it yourself, don’t tell us.

Sorry, but this is a standard attitude based on the fact that building control do not want to be lumbered with this signoff process for Part P. You could rightfully insist that they are being negligent in not having a member of qualified to give sign offs, and, in fact, they are supposed to have been "saving" up all the building control fees by all the electricians who although qualified have not gone for Part P certification and so submit BS7671 certificates and a fee, and taking these fees to either A) train someone up, or B) pay external contractors.

Sorry mate, your building inspector is missinformed.

Like I said, if you want more details, drop me a line.

You can like me, submit it as a "building notice", and in addition, as your work is likely to be less that £2000, the fee should only be £117.50 inc VAT. (I checked your council website, and its the same as mine as we are both in Surrey). Sorry, the documentation about Part P on their is not valid either.

Adam

 

[RogerS]

Well done, Adam...absolutely superb information..definitely bookmarked!

 

[StevieB]

Just my twopenneth, which is an opinion not gospel :wink:

Bottom line seems to be that you need to tell BCO before you start, they will advise, inspect in progress (not covered over work) and test after the installation to conform to part P. This test will either be by a council wallah registered to part P, or an appointed electrician. Everything you plan to do is covered by Part P and should conform to the above.

Reality is councils are swamped. They cannot possibly test every installation. This leaves you 2 choices - get a qualified electrician in and pay him to do it as a registered tradesman (then no need to involve council) or do it yourself and keep quiet. This DIY option depends how confident you are in your own abilities and whether you plan to move in the near future.

You can legally buy the equipment, you can legally install it. You simply have to get it inspected as a consequence of Part P. What's to say you do not 'lose your inspection certificate' ? All you are asked when you move is 'has any electrical work been performed since Jan 2005' yes or no? You could lie, (although as stated colour cable changes may catch you out) or you could say yes but no cert available. Its unclear who is responsible for getting a no cert installation checked - the seller or the buyer (particularly now the house seller pack is not coming or coming in a watered down version).

This time 2 years ago you could do it and no questions were asked. Now you cannot. Its a decision you have to take - are you confident in your abilities, or would you rather have the piece of mind (but added cost) of a spark do it?

Personally I would do it myself or get a spark in. Involve the council and you open a whole can of worms and delays, buck passing and paperwork. Your call at the end of the day.

As to your description of works, I would go with 10mm armoured (consider voltage drop over 35m) and if they are 16A radials I would also have one on an MCB, not 3. Apart from that it sounds fine to me (but I am not a spark!)

Steve.

 

[Wood Monkey]

You’re right, I’ve been fobbed off.

I’m half tempted to submit the BC request, do the job and then call them to say it’s finished, please come and inspect it and see where we go from there. I assume they would have to inform me of the cost before they perform the inspection, at which point I could start the argument (and set Adam on them ;-). I don’t want to end up with a threat of action for non payment. This would still cost me £200 quid (plus the dreaded I suppose), but the job is complete and I have followed the rules of Part P.

The BCO was very ‘clear’ with what he was telling me. It was also very clear that he was not a fan of Part P. Reading between the lines, I could detect that he was trying to put me off, but got the impression he was doing this for my own good. The more I think about it the more it annoys me, after all, my intention is to do it correctly. You should have seen the state of the twin and earth that was there when I bought the house. It was laid at ground level inside 15mm copper tubing pushed together and terminated on a 4 way extension lead that had the plug hacked off and been taped to the twin and earth. If my understanding is correct, I could have connected my new workshop to the end of this and that bit wouldn’t have been subject to the inspection…

Not sure where in Surrey you are Adam, but I think there are variations between local councils. When I questioned why I had to pay £200 to get permission to do a job that they couldn’t stop me doing anyway, the CBO’s answer was very short, so I changed my line of questioning. £200 for what if it doesn’t include inspection and testing costs sounds a little steep…

Jon

 

[Woody Alan]

Hi

Just a couple of observations on this. It may well be worth (from experience) chatting to an electrician who would be prepared to inspect and properly test and sign off for you all your work. Two reasons, firstly until it's tested you don't know whether any of the new kit you've put in is going too work properly e.g your trip/rcd tripping out in the correct time given various fault currents.
Second I have a fair bit of experience in DC power installation in a commercial environment and access to AC electricians (non part P but 16th edition) at work and for every one I asked about how to wire my workshop I got a different answer. I bought the abridged regs book but even then it's misleading as it talks about a seperate earth for outbuildings, but this is very dependant upon the type of supply you have, neutral bonded earth or sheath bonded etc. I put in a seperate earth spike but on testing it failed the earth loop test, a second bonded spike reduced the resistance but still failed. My electrician went back to the NIC his advisory board and found out in this case we could bring the earth from the main board , but in other supply types could be highly dangerous to do this. Doing it this way eliminates any need to talk to the council and getting their "dodgy expert" (sorry always a cynic) as they are not doing the inspecting no need to notify as the electrician signs off work and makes off final connexion. Just my thoughts worked for me and I end up with certificate.

Cheers Alan

 

[dickm]

Possibly not relevant to your particular site, but if you are putting in cable underground, it might be worth getting someone with a "Thrustmole" to save a lot of digging. It's a machine that drives a mole along from the starting point, at preset depth, carrying a pipe behind it. The gas board and water company have both used these locally, and the guys doing it said they could do the same with an armoured cable (and possibly out of hours, for cash....)

 

[johnjin]

Adam

Thanks so much for this information.
It will be very useful in the future.
All the facts are there for anyone to see.
I have printed this thread off for future use.
So thanks again

All the best

John