Regulations regarding power (inverter) in garage, and more!

[thespirit3]

Hi All,

At what point does a 240VAC installation need to be approved? Is it *only* when connected to the mains supply, or anything which is considered 'permanently installed'?

For example, if I was to use a car battery and inverter in the garage with the 240VAC lines 'properly' laid along the walls feeding plug sockets and twin-pole switched lights (a permanent installation) - would I need to notify anyone?

If I then ran some low voltage cables (12 or 24 V AC or DC) from a transformer in the house, along the garden wall and to the garage (providing a means to trickle-charge the battery) - would this alter things? I suspect not as the transformer would mean the supply was isolated from the mains... but best to check!

I'm aware of the capabilities of inverters, current drain, voltage drop on low voltage garden line etc - so this is more of a legal question than technical.

edit: I should add, I can't currently afford to run 240VAC from the house to the garage (armoured cable, cost of qualified electricians time etc) so this is my DIY solution to the problem - providing it's legal


Thanks,


Steve

 

[timtheenchanter]

being picky, then 240V IS low voltage.

you said it yourself "a permanant installation" weather or not it is fed from the grid, a generator or an inverter doesnt make the 240V any different (generally speaking, please dont get picky with modified sines etc)

not done the calcs, but im sure you would need a pretty beefy cable to take the 12/24V to get a decent current at the other end, what sort of charging rate are you after??

an 85AHr leisure battery at 500mA (trickle) would take 150+hrs to fill from flat.
most caravan chargers (designed to do what you suggest) are 9A upwards charging current.

 

[holmslaw]

..

 

[thespirit3]

Thanks for the replies but I could do with some clarification.

There would be little current drain in the garage (occasional lighting, no powertools etc) so the 12/24V line would literally provide a maintenance charge. It's a cheaper solution compared to using a solar panel! My main concern is the rules/regulations and potentially voiding my insurance.

So, the fact it's a permanent installation would mean a qualified electrician would need to install this, despite the fact it's not connected to the mains supply?

What if I ditched the inverter and simply ran a permanently installed 12V lighting system?

I guess that's what I'm getting at - at what point does this need to be done by a qualified electrician? Is the requirement any installation connected to the mains, any 'permanent installation' (at 240VAC regardless of source), any 'permanent installation' regardless of source or voltage, or some combination of these?

Using a silly example - I can't imagine I'd need a qualified electrician to install a 3V torch bulb holder on the ceiling connected to some D cell batteries via a switch - but this setup could be permanentlly 'installed' too.

Edit: I've been reading http://www.theiet.org/publishing/wiring-regulations/part-p/ (spec parts 5 and 11) and it still doesn't make this clear

Steve

 

[holmslaw]

..

 

[electronicsuk]

edit: I should add, I can't currently afford to run 240VAC from the house to the garage (armoured cable, cost of qualified electricians time etc) so this is my DIY solution to the problem - providing it's legal

The inverter/battery/cabling required by what you propose could cost easily twice what an electrician who's a member of a self certification scheme carrying out the work would cost you.

 

[thespirit3]

Thanks for the responses. I'm getting a quote for a proper installation. I'll then review my options.

Thanks again,


Steve

 

[ban-all-sheds]

And "electrical installation" is defined as "fixed electrical cables or fixed electrical equipment located on the consumer’s side of the electricity supply meter".

So no distinctions re temporary/permanent, and the regulations apply to anything working at up to 1000 volts between conductors or 600 volts between conductors and earth (AC) or 1500 volts between conductors or 900 volts between conductors and earth (DC)

 

[thespirit3]

Thanks for the information.

Surely all sorts of DIY installs must fall foul of this?

In previous houses I've fitted spur sockets off an existing ring, changed and moved light fittings, light switches, fitted low voltage transformers & lighting - and now if I understand correctly, all the above would be illegal and require a certified electrician?

Seems strange I can legally service a CRT TV risking exposure to HT voltages, yet I can't run a simple mains spur (or in my original question, a battery/inverter based installation).


Steve

 

[ban-all-sheds]

You need to read Schedule 2B.

 

[thespirit3]

OK, I've had a quote from a supposedly qualified electrician who's told me the following:-

1) The garage can be fed by taking a spur from the nearest house ring main.
2) As the cable running between house and garage will be armoured, this can simply be laid on the garden behind some trellis.

Doing some online reading myself it appears 1) is incorrect as power to a garage must be taken from the main internal consumer box (not from an existing ring). 2) also seems suspicious - is it true this can simply be laid along the surface of the garden behind some trellis/fencing?

He's quoted £530 for the job but doesn't fill me with confidence. I've requested a second quote from another company.

Any clarification on the rules would be useful. I don't want to be £500 out of pocket and still be breaking the regulations!


Thanks

 

[holmslaw]

..

 

[maltaron]

Reading the part P link posted by BAS it clearly states that Part P only applies when the power in a garden or outbuilding is sourced from the dwelling, therefore a local supply i.e. invertor is free of Part P. This is not to say that the 240v side of the invertor is free of installing and testing as per regs.

 

[electronicsuk]

2) As the cable running between house and garage will be armoured, this can simply be laid on the garden behind some trellis.

He's an incompetant clown. External cables have to be buried at a safe depth or supported at a safe level above ground.

Indeed. And the quote does seem a little steep, too, considering he doesn't intend to do the (presumably more difficult) job of running a new circuit back to the CU. Of course, we haven't seen the job, so your second quote may provide a better indication if it's in a similar ballpark.

 

[securespark]

And "electrical installation" is defined as "fixed electrical cables or fixed electrical equipment located on the consumer’s side of the electricity supply meter".

So an installation running independent of the consumer's side of the supply meter does not fall under the jurisdiction of part P.