Supply to summer house.

[PAD66]

Been asked to install 3 X sockets 1 X light 1 X PIR light into a summer house. The building is 45 mtrs away from the house and I'm unable to wire back to the board. My plan is to take a fused spur of the ring and use a 4mm SWA to feed the summerhouse. In summerhouse I intend to install a 2 way garage unit for the circuits. My query is would you use a RCD main switch or a normal isolator. The ring Is RCD protected already. My other question is this a minor works or installation certificate. My thoughts are minor works as it is an alteration to an existing circuit.
Thanks.

 

[HappyHippyDad]

Have you worked out the Volt drop for the run PAD? 45m sounds quite a long way. Also, I know it's perfectly acceptable to take a spur for shed power but it would be better to have a seperate MCB.

There really isn't any point in having 2 rcd's on the same circuit, it's already got RCD protection from the main CU.

I was about to say minor works cert (MWC) as you're not adding a new circuit, but you are installing a CU... so it's notifiable and would need an electrical installation cert (EIC)... I think... tired...someone else will confirm!

 

[PAD66]

Done a calc for volt drop 4mm is ok, did think of using 6mm but thought it was a bit over the top as it just running a fridge and a couple of lights. Got a log burner in there so not going to be used for heat. Did think of just using a double pole switch and FCU for the lights.

 

[uksparks]

For what it costs I'd just stick a bigger cable in.

the spur element of it only needs a minor works but the new CU needs an EIC, however, you should be able incorporate both into the EIC.

 

[uksparks]

The supply is only going to ha e a 13A fuse in it, so whatever you put in the garage unit will need to be smaller for them to be of any benefit I suppose, Hager do MCBs starting at 1A.

 

[davesparks]

What is the point of installing a CU in this shed? If the supply is already fused at 13A then the MCBs won't be achieving very much at all!

This smacks of very poor design!

 

[PAD66]

Your right there is no point in fitting a CU, overthinking it as usual. Just stick with a FCU at the house and just use a 20 amp switch at the Summerhouse to isolate and fuse the lights down. Wants going back to the board really, but no way to it without major alterations.

 

[davesparks]

A 20A switch to isolate and fuse the lights?

If it needs major work then do major work, bodging it because you don't want to do it properly is hardly a professional approach

 

[Pete999]

Will your installation be safe then???? as for certificate you are an electrician, should you be asking these question??

 

[Dave OCD]

Still too many posts that come across as rather hostile on here IMO.

 

[Dave OCD]

A 20A switch to isolate and fuse the lights?

If it needs major work then do major work, bodging it because you don't want to do it properly is hardly a professional approach

Unfortunately in the real world Dave there's a point where cost can outweigh the benefit and you have to compromise on how you do the job to keep it affordable - obviously not cutting corners with safety or contravening regs but a 13amp supply is usually perfectly adequate for a summer house where electric heating isn't required - I have 3 sheds running off one FCU at the house, never blown the fuse yet. Lights simply run from seperate FCUs C/W 3 amp fuses. :smiley2:

 

[Deleted member 9648]

Don't take this as criticism of the OP, it's not intended to be, but I cant help but wonder at such a simple installation confusing an NICEIC DI......Maybe the NICEIC need to have a look at the level of experience required as an approved DI.
If I was really cynical I might think just for a moment that all they are interested in is the fees.....surely not?

 

[Guest77]

I am also not going to try to upset the OP, all I will say is the whole design is wrong and IMO another good think about the whole installation should be considered.

 

[Andy78]

Still too many posts that come across as rather hostile on here IMO.

You're reading them wrong.
It is perfectly reasonable for a forum of professional electricians to question the installation, design, and certification of a person who is supposed to be entirely competent in carrying out the said tasks and who is asking for advice and criticism of the proposed works.

I think that the issue of competency in the workplace in our industry, and making sure that the question asked is guided in the right direction to produce a safe and compliant job is of far greater import than worrying about inferred tones on an internet forum.

 

[davesparks]

Still too many posts that come across as rather hostile on here IMO.

GIGO - Garbage in, Garbage out

 

[davesparks]

Unfortunately in the real world Dave there's a point where cost can outweigh the benefit and you have to compromise on how you do the job to keep it affordable - obviously not cutting corners with safety or contravening regs but a 13amp supply is usually perfectly adequate for a summer house where electric heating isn't required - I have 3 sheds running off one FCU at the house, never blown the fuse yet. Lights simply run from seperate FCUs C/W 3 amp fuses. :smiley2:

What you do in your own house is up to you, but if you sell that to a customer as an installation design then that's a different matter.

I don't see how spurring from a ring circuit to feed a summer house gives good segregation of circuits or minimises the potential disruption in the event of a fault.

 

[Dave OCD]

I understand your point Andy but there's a lot to be said for guiding people rather than scaring them away never to seek advice again. The issue of competency in our trade is a very thorny one indeed, with monotonous regularity I come across work by 'registered' electricians which is rough beyond belief , they generally put all the right stickers on though.

 

[Deleted member 9648]

My gripe is not with the OP, (who clearly has taken the correct course in asking for advise which proves he wants it to be right)....but with the NIC. Personally I don't think it's unreasonable to expect an installer registered as competent by the NICEIC to be able to design an install like this without assistance

 

[Dave OCD]

What you do in your own house is up to you, but if you sell that to a customer as an installation design then that's a different matter.

I don't see how spurring from a ring circuit to feed a summer house gives good segregation of circuits or minimises the potential disruption in the event of a fault.

All I'm saying is that practicalities need to be considered, in my case it was the simplest safe option, much easier than getting a dedicated supply right round the other side of the house with the associated disruption. The only way to achieve truly minimal disruption in the event of a fault is exclusive use of RCBOs and in my experience 60-70% of customers don't see the benefit and don't want the additional cost.

 

[GMES]

To be fair to all in this thread including the op, the questions are pretty basic and anyone undertaking the work as a professional tradesman should know the answers to those questions and if they don't they shouldn't be working alone, That's not a dig at the op but a valid point. As for member replies to be fair I don't see anything nasty or argumentative just genuine concern, sometimes text can come accross the wrong way but is not meant that way. A couple of members have raised concerns about the installation method and design which for me is what the forum is here for.