Shed project

[Engagesafetysquint]

Hi all.
New to the forum and not really clued up on proper terminology so bear with me.

I want to rig up my new shed with 4 double sockets for items such as battery tool charging,bench top grinder , bench top drill press + small lathe.
I also want a lighting circuit which will power 3x 1200mm LED strip lights.
Problem comes with getting power to the shed.
I need to run 15.5 M from the house consumer unit.
I have used a online calculator that has told me I will need 4mm SWA.
Ok. Now the big question.
Can I run the SWA from a spare 32a mcb in the house consumer to a RCD in the shed with a 32a + 6a mcb.
I want to run the double sockets of the 32a from the RCD in a ring circuit to give me the possibility of adding sockets in the future if needed.
Is this possible, and importantly would a sparky be happy to take on the job as described?
Thanks

 

[UNG]

One that that often gets missed especially as the weather is getting colder are you planning for any heating

 

[Fleeting]

I imagine you would find an electrician to undertake it the hardest part getting the supply cable from A to B. It may be possible to replace the 32A device with something higher, assuming parts are still available to give you more capacity.

 

[Engagesafetysquint]

No, I just wear a warm jumper. At the very most I will have a small low watt bar heater set up under the lathe to keep the surfaces corrosion free.

 

[Engagesafetysquint]

I imagine you would find an electrician to undertake it the hardest part getting the supply cable from A to B. It may be possible to replace the 32A device with something higher, assuming parts are still available to give you more capacity.

You mean in the house consumer?
I was looking at running the cable from a weatherproof box outside the house on the wall directly adjacent to the consumer then run the cable with cleats along the outside wall which transfers directly to a brick garden wall which runs right behind the shed.
Can you tell me in basic terms why I’d need more than 32a in the consumer unit?
Thanks

 

[Fleeting]

You mean in the house consumer?
I was looking at running the cable from a weatherproof box outside the house on the wall directly adjacent to the consumer then run the cable with cleats along the outside wall which transfers directly to a brick garden wall which runs right behind the shed.
Can you tell me in basic terms why I’d need more than 32a in the consumer unit?
Thanks

Yes between the house and shed. It is often better to oversize a supply for future expansion plus with 32A devices at both ends you won't achieve selectivity (which one will trip first) but having said that selectivity is difficult to achieve with circuit breakers anyway unless you use extremes of sizes.

 

[Engagesafetysquint]

Thanks, I’ll have a look and see if a bigger RCD is attainable.
Does the rest of the system sound ok/ legal?

 

[Fleeting]

Thanks, I’ll have a look and see if a bigger RCD is attainable.
Does the rest of the system sound ok/ legal?

That is for your electrician to decide.

 

[Engagesafetysquint]

Cheers, what I want to know is the electrician going to laugh in my face when I ask him if my thoughts are viable, or am I barking up the wrong tree.
In an ideal world I’d like to run it past him, run all the cable to the boxes, and then let him do the magic bits.
I haven’t asked any electricians to come and see the job yet so I wanted to get a steer from folk on here beforehand.

 

[Fleeting]

Some will let you do some of the donkey work some won't. As for your methods some may say that is fine others may choose alternative methods.

 

[kerching]

I'd go for a 6mm SWA minimum
Also I wouldn't bother with rings.......not installed one in over 20 years, go radial; it's the future

 

[Murdoch]

Don't do anything before finding a spark .......

 

[Engagesafetysquint]

Don't do anything before finding a spark .......

Cheers, I’m not going to. I just wanted to arm myself with a bit of a clue before I went looking for one.
I want to get involved with the job if I can so hopefully I can find someone who’s willing to talk with me and let me do the donkey work.
I’m a mechanical engineer by trade, can’t see electric so I don’t trust it!

 

[mort2376]

I'd go for a 6mm SWA minimum
Also I wouldn't bother with rings.......not installed one in over 20 years, go radial; it's the future

Agree with above. 6mm swa. Fed via 40a mcb. Then either a 20a 2.5mm radial or a 32a 4mm radial for sockets. 6a 1.0mm circuit for lights.

This arrangement allows for expansion. Also rather than a single rcd fit rcbos that way if sockets trip your not plunged into darkness !

 

[kerching]

The last "shed" I did I also fitted some emergency lights! Mind you he did have a Bridgeport, 3' gap bed, metal former and a few other toys. Theory was he works in there most nights and is no spring chicken so if the power failed he can get out without tripping over stuff OR if the lights fail and he is operating a spinny around machine he is safer

 

[BorisJ]

I assume you have a RCD in the house CU. If so you do not need of want RCD or RCBOs in the shed. There will be no discrimination and both will go with a fault.