Shed electrical requirements

[Rtcdude]

I’m planning on putting in a small (10x10) detached shed for garden storage plus a freezer for meat storage, an in-wall AC unit (for temperature sensitive seedlings), and a few outlets and lights. The interior would be fully insulated and Sheetrock finished. I was planning on a 100amp,12 position, sub panel with a buried conduit service from the house (about 30’). There would likely be a minimum of four circuits, two appliance (fridge and AC), one for outlets and one for lights (both GFI’ed). The question, do I need an external device disconnect, for firemen access, or will a main breaker in the sub panel be OK? The shed could be locked a lot of the time, so interior access might not be always possible. Also, will the shed need it’s own grounding rods?

 

[Midwest]

@Megawatt think might help.

 

[Megawatt]

I’m planning on putting in a small (10x10) detached shed for garden storage plus a freezer for meat storage, an in-wall AC unit (for temperature sensitive seedlings), and a few outlets and lights. The interior would be fully insulated and Sheetrock finished. I was planning on a 100amp,12 position, sub panel with a buried conduit service from the house (about 30’). There would likely be a minimum of four circuits, two appliance (fridge and AC), one for outlets and one for lights (both GFI’ed). The question, do I need an external device disconnect, for firemen access, or will a main breaker in the sub panel be OK? The shed could be locked a lot of the time, so interior access might not be always possible. Also, will the shed need it’s own grounding rods?

You are on the right track and 100 amps sounds a little big for a 10 by 10 building but yes you can install a sub panel and what I do is a main lug only panel. You need to pull 4 wires with being 2 lives, 1 neutral and 1 ground wire, and your building does not require ground rods. Install a breaker to feed the building in your main panel and you are not required to have a disconnect on your building like you do your house. Your ditch needs to be at a minimum of 18 inches deep. Try a 60 amp panel and you should be fine.

 

[Rtcdude]

What size of wire should I use for the buried feed?

 

[Megawatt]

What size of wire should I use for the buried feed?

If you use the 60 amp option then # 6 wire and it needs to be approved for under ground use. Don’t use the 100 amp since we have a lot whole houses on 100 amps. You will save money using the 60 amp option.

 

[Megawatt]

What size of wire should I use for the buried feed?

If you use the 60 amp option then use # 6 wire which has to approved for outdoor use.

 

[Megawatt]

If you use the 60 amp option then use # 6 wire which has to approved for outdoor use.

What size of wire should I use for the buried feed?

I guess I answered you twice but good luck.

 

[Rtcdude]

I guess I answered you twice but good luck.

One more quick question. I have always used nail plates on studs to protect RomEx cables from sheetrock screws/nails; a best practice issue. But are nail plates required by NEC rules. Thanks.

 

[Megawatt]

One more quick question. I have always used nail plates on studs to protect RomEx cables from sheetrock screws/nails; a best practice issue. But are nail plates required by NEC rules. Thanks.

Yes they are required by the NEC

 

[pc1966]

I had to look up 'nail plates' over the pond as they are not really seen in the UK. For those how have not seen examples, here are the things:

https://www.crum.com/140593/Category/Nail-Plates-for-Studs

The UK rules here are a bit different, we need RCD protection (GFCI at the panel) for buried cables less then 50mm (2") from wall surfaces and that lack earthed armour or similar means to automatically disconnect on penetration damage. We also define "safe zones" where cable ought to run so folks know not to hammer in stuff and that also has distances from wall surfaces, etc:

Electrical Safe Zones: Running Cables Through Walls and Floors

Find out about the designated electrical safe zones that have to be obeyed when running electrical cables through walls and floors

www.diydoctor.org.uk

Of course folks still drill in to the zones they should not, and folks still run cables outside of where they should. Such is life!