Feed to Shed

[EFLImpudence]

Do you really mean from a ring final?

Yes.

Why I asked that was because, surely, lots of things which are not BS1363 are supplied from a ring final.
For example: washing machines, fridges, televisions et al.

The regulation in question, 433.1.204, says:
Accessories to BS1363 may be supplied through a ring final circuit.
It does not say:
Accessories to BS1363 may be supplied only through a ring final circuit - obviously not the case - or
Accessories to BS1363 only may be supplied through a ring final circuit.

What about grid switches?

Anything can be supplied through a ring final circuit (if the need arises, e.g. VD). The only difference in this case is the allowed reduced csa of the conductors and variable load sharing. What difference does that make to an accessory?
What difference is a radial final of the same characteristics?

We've had all this before.

Do you really want to debate it again?

 

[RyanM]

Hi Guys,

With regards the fused spurs all over....I have separate ones for: Extract fan, washing machine, oven, hob extract and fridge freezer - all built in, so not accessible sockets to isolate otherwise. I think it seems quite normal to be honest?!

I'm going to get the paving done, so I will pull out the old cable completely, get a new SWA cable laid under the paving for someone to come around, connect and sign off. Suppose 1.5mm will be ok off the 5A fused spur.

I was thinking though, what if the SWA was originally connected to the live side of the FSU? Is that legit? As then that would be a spur off the ring? I'm not even sure the wires would all fit in the FSU to be honest, haha.



Thanks a lot

 

[ban-all-sheds]

I'm going to get the paving done, so I will pull out the old cable completely, get a new SWA cable laid under the paving for someone to come around, connect and sign off.

It doesn't work like that. Be prepared to be disappointed.

Suppose 1.5mm will be ok off the 5A fused spur.

It will, as long as you'll never want a load >3kW. If you do then be prepared for another disappointment of having to dig up your paving because you scrimped on the cable you put in.

I was thinking though, what if the SWA was originally connected to the live side of the FSU?

Was it?

Is that legit? As then that would be a spur off the ring?

You are allowed unfused spurs from ring finals.

I'm not even sure the wires would all fit in the FSU to be honest, haha.

Of course they will.

 

[ban-all-sheds]

It does not say:

Accessories to BS1363 only may be supplied through a ring final circuit.

No, it does not explicitly say that.

But then neither does it say that anything other than BS 1363 accessories may be supplied by a ring final in the context of 433.1.204.

The only difference in this case is the allowed reduced csa of the conductors and variable load sharing. What difference does that make to an accessory?

None, but it makes a difference as to whether you're allowed to have a circuit with In > Iz in the first place.

What difference is a radial final of the same characteristics?

Do you mean a radial with In > Iz used to supply loads of a nature which mean the cable can be overloaded?

 

[RyanM]

I'm going to get the paving done, so I will pull out the old cable completely, get a new SWA cable laid under the paving for someone to come around, connect and sign off.

It doesn't work like that. Be prepared to be disappointed.

Why?

Suppose 1.5mm will be ok off the 5A fused spur.

It will, as long as you'll never want a load >3kW. If you do then be prepared for another disappointment of having to dig up your paving because you scrimped on the cable you put in.

What are my other options? It's a mid terrace, concrete floors, CU at the front of the house. This is probably why the current feed is fed from the FSU

I was thinking though, what if the SWA was originally connected to the live side of the FSU?

Was it?

Who knows?! Hence my thought...

Is that legit? As then that would be a spur off the ring?

You are allowed unfused spurs from ring finals.

True. So it is probably worth putting in some 2.5mm.

I'm not even sure the wires would all fit in the FSU to be honest, haha.

Of course they will.

Glad they will then without looking, which means a bigger cable, and more can be ran from it.

 

[ban-all-sheds]

Why?

With my emphasis:

I being the person responsible for the design, construction, inspection & testing of the electrical installation (as indicated by my signature below), particulars of which are described above, having exercised reasonable skill and care when carrying out the design, construction, inspection & testing hereby CERTIFY that the said work for which I have been responsible is to the best of my knowledge and belief in accordance with BS 7671:2008, amended to 2015 except for the departures, if any, detailed as follows:​

If he doesn't do the design & construction, how can you expect him to sign to say he did?

And how can he inspect the cable if you bury it under paving?

Also, if this counts as a new circuit, that becomes notifiable, so if you do the work you have to apply for Building Regulations approval in advance. The alternative is to use a registered electrician who can self-certify compliance. But again it means that he does actually have to do it.

It's not as bad as it seems. Few, if any, electricians are frustrated navvies, so there will be no problem with you digging the trench, which is by far and away the largest part of this job.

So...

1. Find an electrician, discuss the route, depth and preparation of the trench
2. You dig the trench and prepare the base
3. Electrician lays the cable and connects or makes safe the ends
4. You backfill the trench. Possibly while he drinks tea and watches , or while he sorts out the wiring in the shed
   
5. Testing & issuing the certificate.

What are my other options? It's a mid terrace, concrete floors, CU at the front of the house. This is probably why the current feed is fed from the FSU

An experienced electrician can find ways to get cables from A to B that you probably wouldn't think of. But TBH it sounds like it would cost a lot, and if it's just a small shed with a few sockets, too much. You'd probably need to have fairly definite plans to put a kiln, or a hot-tub, or a particle accelerator out there for it to make sense to put in a larger supply just-in-case.

True. So it is probably worth putting in some 2.5mm.

Or even larger. Or have it run in an underground duct so it could be replaced.

But fused or unfused, 1.5mm² will be large enough for any loading which could be on a spur from a ring final.

Glad they will then without looking, which means a bigger cable, and more can be ran from it.

For as long as you are spurring off the ring you will never be able to run more in the shed than a 1.5mm² cable can cope with. 2.5mm² would happily carry 25-30A, but a spur from a ring may not. Putting in a larger cable would allow the supply to be used for more in the future but only if you can get a dedicated circuit from the CU to the external junction box.

 

[ban-all-sheds]

Now I'm in, and investigating things, there was actually no power in the shed.

Are there any sockets, lights, switches, cables etc installed in the shed?

 

[RyanM]

Are there any sockets, lights, switches, cables etc installed in the shed?

Yes, two sockets, but the cable's have been removed between them, and the junction box.

 

[RyanM]

With my emphasis:

I being the person responsible for the design, construction, inspection & testing of the electrical installation (as indicated by my signature below), particulars of which are described above, having exercised reasonable skill and care when carrying out the design, construction, inspection & testing hereby CERTIFY that the said work for which I have been responsible is to the best of my knowledge and belief in accordance with BS 7671:2008, amended to 2015 except for the departures, if any, detailed as follows:​

If he doesn't do the design & construction, how can you expect him to sign to say he did?

And how can he inspect the cable if you bury it under paving?

Also, if this counts as a new circuit, that becomes notifiable, so if you do the work you have to apply for Building Regulations approval in advance. The alternative is to use a registered electrician who can self-certify compliance. But again it means that he does actually have to do it.

It's not as bad as it seems. Few, if any, electricians are frustrated navvies, so there will be no problem with you digging the trench, which is by far and away the largest part of this job.

So...

1. Find an electrician, discuss the route, depth and preparation of the trench
2. You dig the trench and prepare the base
3. Electrician lays the cable and connects or makes safe the ends
4. You backfill the trench. Possibly while he drinks tea and watches , or while he sorts out the wiring in the shed
   
5. Testing & issuing the certificate.

Hi, Ok, thanks for that, I understand now.

Genuine question though - if I wanted my house testing, to prove everything is safe, along with a certificate, how does that work, as the electrician won't have done any of the above? Including the current feed to the shed?



Thanks

 

[Taylortwocities]

A CERTIFICATE is for new work.

For existing installations, you need to ask a competent electrician for an EICR - Electrical Installation CONDITION Report.
More info here
http://www.electricalsafetyfirst.or...pection-explained/guide-to-condition-reports/

 

[ban-all-sheds]

And an EICR does not count as the "signing off" which you think you'll get an electrician to do after you have installed the cable.

 

[Markymark240674]

Stick 500v down that sucker