Outbuilding power

[Deanthemanc]

Hi all

Advice needed

I am converting a Victorian out building into a utility and would like 2 double sockets and a light.

The building is 1.25m from the back of the house.

At the moment there is an weather proof double socket on the external wall at the back of the house which is part of the laundry sockets ring main.

Can I extend this ring main into the outbuilding?

If so what are the procedures and if not what are my options

Your help is appreciated

 

[PrenticeBoyofDerry]

You can extend the ring final circuit(RFC), but I would consider the loading of the appliances in the utility and the load already demanded on the existing RFC.
I would always recommend outside sockets were independently'locally isolated, so they can be disconnected from the supply of the RFC without power loss elsewhere, this is a provision against fault of outside socket causing power loss and will also prevent mischievous use of socket.

I would look at the information available of circuit design, permitted safe routes and RCD protection. A browse through wiki would give some help.
I would also always recommend that electric installation are inspected prior to work staring and throughout the procedure of and on commissioning, and this information be compliant to the standards and documented in the correct forms.

 

[Deanthemanc]

Thanks for the advice

A builder friend said to me that I may be able to add a garage style cu into the ring main, but I thought that an addition cu would have to be directly wired to the main cu

Can this be done?

 

[flameport]

You cannot connect a consumer unit to a ring final.
One could probably be connected to your existing consumer unit, however for two sockets and a light, a CU is not required at all.

 

[Deanthemanc]

So if I tie into the ring with junctions boxes and 2.5mm t&e then extend the ring into the outbuilding to create 2 double sockets, then spur off one of those into 1.5mm cable then 5a fuse then connect the switch and light.

I would encase the 2.5 in plastic trunking

Does that all sound OK

I'm only having a dryer and washer in the outbuilding. The other socket will be for occasional use only. Charging drill batteries etc

 

[ericmark]

Likely using a fused connection unit (FCU) as you say would work without a problem. However as to if it would comply with regulations is another question.

Any appliance which is not portable and due to weight a tumble drier and washer are not classed as portable should have a dedicated supply if over a 2kW draw. So the extension is will likely have over a 2kW draw and so should have it's own supply.

I personally would not bother to my mind the 13A fuse in the FCU means it will fail safe so simple FCU is all that is required. The only problem is if the work needs passing by some one who's a jobs worth.

 

[EFLImpudence]

Likely using a fused connection unit (FCU) as you say would work without a problem. However as to if it would comply with regulations is another question.

It would appear that it has been decided to extend the ring so no FCU.

Any appliance which is not portable and due to weight a tumble drier and washer are not classed as portable should have a dedicated supply if over a 2kW draw.

That may be the recommendations - not regulations - but is no different than using the appliances in the kitchen where it is extremely unlikely that dedicated circuits would be installed for WMs and Driers.
Are they, in fact, over 2kW?

So the extension is will likely have over a 2kW draw and so should have it's own supply.

That would be better but, again, if it were the kitchen ???

I personally would not bother to my mind the 13A fuse in the FCU means it will fail safe so simple FCU is all that is required. The only problem is if the work needs passing by some one who's a jobs worth.

I'm not sure where the FCU came from or is supposed to go.
Will the work need 'passing'?

 

[EFLImpudence]

So if I tie into the ring with junctions boxes and 2.5mm

Use an existing socket or fit a new one instead of using JBs.
If from the existing then one cable will be connected to the socket and the other can be connected with terminal blocks or similar.

then extend the ring into the outbuilding to create 2 double sockets, then spur off one of those into 1.5mm cable then 5a fuse then connect the switch and light.

Yes - 1mm² will be more than adequate with 10A (actually 15A) over-capacity.

I'm only having a dryer and washer in the outbuilding.

That's not really an 'only'.

 

[PrenticeBoyofDerry]

A builder friend said to me that I may be able to add a garage style cu into the ring main, but I thought that an addition cu would have to be directly wired to the main cu
Can this be done?

Your builder friend needs to stick to bricks and mortar as they are offering you incorrect advise.

As mention previously you can extend the RFC in to the utility, add two sockets and then down fuse via a FCU for a functional light.
or you could install FCU at intersection of RFC then have the two sockets down fused to 13A and then take a second FCU to down fuse for lighting.
Be be aware that this part of the circuit will be restricted to a maximum demand of 13A on option 2, for both sockets and light. Could be an issue if both appliance are operating at the same time.

 

[JohnW2]

Any appliance which is not portable and due to weight a tumble drier and washer are not classed as portable should have a dedicated supply if over a 2kW draw.

That may be the recommendations - not regulations - but is no different than using the appliances in the kitchen where it is extremely unlikely that dedicated circuits would be installed for WMs and Driers. ... Are they, in fact, over 2kW?

If we are talking about BS7671 itself (goodness knows what the OSG 'recommends' - I don't currently have mine to hand), I don't think that it even 'recommends' what eric suggests. I suspect (given that he mentions 2KW) that he is thinking of the guidance in ('informative') Appendix 15 that, in order to reduce the risk of overloading the circuit, "cookers, ovens and hobs with a rated power exceeding 2kW" (not WMs or driers) should not be connected to a ring final circuit, but should have their own dedicated radial circuits. It does also say that, for the same reason, "immersion heaters, comprehensive electric space heating or loads of a similar profile" should not be supplied by ring finals - but it doesn't mention 2kW, and I'm far from convinced that WMs and driers (which, after all, are usually operative for relatively limited periods of time) come into that category, anyway.

Despite those 'guidances', how often have you, I or eric seen a washing machine or drier provided with its own dedicated radial circuit?

Kind Regards, John

 

[PrenticeBoyofDerry]

Despite those 'guidances', how often have you, I or eric seen a washing machine or drier provided with its own dedicated radial circuit?

I tend when rewiring and when doing utilities.

 

[JohnW2]

Despite those 'guidances', how often have you, I or eric seen a washing machine or drier provided with its own dedicated radial circuit?

I tend when rewiring and when doing utilities.

A separate dedicated radial circuit for each appliance (WM, DW, dryer etc.)?

Kind Regards, John

 

[ban-all-sheds]

I would also always recommend that electric installation are inspected prior to work staring

It's another tiring day for PBoD...

 

[AndyPRK]

I should think it is with these inspections, radial installations, and rcd recommendations.


Must be paid by the hour.

 

[PrenticeBoyofDerry]

Just making sure there is nothing wrong with the installation before I start adding on to it.
Resulting hopefully in a non-problematic installation/addition and a truthfull reflection on the real cost of the work. Nothing to do with hourly rates doing the customer a service, not firking them about with incompetent plug and play installations and add ons because a fault or issue had not been spotted before resulting in possible power loss and additional costs.
It's not hard to do continuity, IR, Zs and RCD tests and get it right for the customer first time round.