Garden power

[Cartman]

Hope someone can help. At present I have a powered shed and a koi pond in the garden that are connected as follows

The shed runs off of a spur on the socket ring main and draws about 700W.
The power for the pond runs off of the cooker circuit which seems to be a radial circuit from the main consumer unit. I do not use this for the cooker and so only powers the pond. This circuit is connected via an armoured cable to a secondary consumer unit in a pump house and draws about 30A at full load (mostly due to a heater.) In effect, it has just extended the cooker radial circuit to a secondary consumer unit and the pond equipment runs off that.

I am however installing a new shed and a new cooker that will need the cooker circuit. I am therefore looking to rewire the garden. I am intending to run an independant armoured cable line from the consumer unit to feed the pond system and two sheds. My question therefore is :-

1. Do I need to run the dedicated armoured cable feed as a radial or ring main
2. Can one armoured cable feed into a secondary consumer unit that then split the power to the pond and the two sheds or should I run three circuits (either radial or ring) from the main consumer unit to the two sheds and the pond ?

Many thanks for any advice

 

[Chri5]

. Do I need to run the dedicated armoured cable feed as a radial or ring main
2. Can one armoured cable feed into a secondary consumer unit that then split the power to the pond and the two sheds or should I run three circuits (either radial or ring) from the main consumer unit to the two sheds and the pond ?

Radial, taking account of load and distance for size- There's a cable cal section on the TLC electrical suppliers site.

Yes, run a single cable from the existing CU or via a cut out and on the the henly block. Then have a sub mains CU (builders CU is perfect) with fuses for each circuit that you wish to provide for.

Work is notifiable under Part P

 

[Cartman]

Chri5 thanks for that. Got to love part P ! Generally will electricians certify someone else's work if it's left exposed for them to see or am I being woefully optomistic ?

 

[Taylortwocities]

Most are only able to self cert work they have done themselves. Me included.
Most are so busy that they cant be bothered with doing the unprofitable bits of a job and then putting their name to it. Me included!

If you are going to DIY it then notify LABC before you start and they will inspect and should test & cert it for their fee.

 

[Murdochcat]

Yep, indeed - provided that, as I said, the radial circuit coming from the garage each had their own OPDs in the garage CU.

On the other hand, if there were no OPDs in the garage, with the feed from an OPD in the house splittig into what the OP calls 'two radials', then I think that, in electrical terms, there would be only one (branching) 'radial final circuit' (all the way from OPD in house, and no "sub main". Do you agree?

Is there is only one OCPD there is only one circuit

 

[JohnW2]

Is there is only one OCPD there is only one circuit

Yes, that's what I said - we therefore appear to be agreed.

 

[ebee]

Well you could run it all as 1 or 2 or 3 circuits or as many circuits as you like, the number of ways free to do that in your existing consumer unit might sway your decision somewhat and will effect the resiliance to some degree, not forgeting that it all starts life as "one circuit" anyway (at the cut out).

As said, it comes under Part P anyway, if you constrive to justify your works as just an addition to an existing circuit rather than any new circuits then you might save the expense of notification.
A "normal" registered electrician with a scheme should not pass this works off as their own although some schemes did allow some of them to do inspection a certify as a third party as long as they had additional qualifcations and insurance and gave a good degree of supervision of the job.