Thread: House to shed power cable size/type

Originally Posted by bee utey

A suggestion would be to replace all circuit breakers where possible with single gang RCDs which would free up a couple of spaces by removing the older style RCDs which feed multiple breakers.

Originally Posted by Vern

A little confused with what you have Justin, but assuming the 10a rcd feeds the shed and this is what you are replacing with the 6mm?
If so just get a 32 a CB for the main switchboard new shed supply, then get a little sub board and run a couple of circuits from that, using rcbo's to protect you final sub circuits.

Nothing says pro more than a diagram drawn using Paint. Also, pictures say everything I want to say...



P.S. Don't blame me for this set-up! I didn't do it!

Interesting job! I like the main switch in the middle there!

So you have two phase supply I see, and no room in the switchboard.
I'd double the two light circuits up on the left hand side (unless they have an ixl tastic on each), and use that for the new shed supply, except replace the breaker with a 32a and take it off the rcd. Then install such board in shed on new 32a supply.

Originally Posted by Vern

Interesting job! I like the main switch in the middle there!

So you have two phase supply I see, and no room in the switchboard.
I'd double the two light circuits up on the left hand side (unless they have an ixl tastic on each), and use that for the new shed supply, except replace the breaker with a 32a and take it off the rcd. Then install such board in shed on new 32a supply.

Yes, there is a lot of interesting things around this house. Last guy was definitely DYI, but I kind of wish he wasn't!

Brilliant suggestion now I think about it. Reasons being:

We have 1 IXL, but I just went and checked and it's on the right hand side lights CB anyway.
The 2 light CB's on the left are only 10A+16A (rather than 16+16).
The right hand side is loaded with spa + A/C, which are both big breakers.

So shed on the left with a separate breaker seems perfect. Exactly what I was going for - I just didn't know how best to get there!

Originally Posted by bee utey

A suggestion would be to replace all circuit breakers where possible with single gang RCDs which would free up a couple of spaces by removing the older style RCDs which feed multiple breakers.

After looking at your board, RCDs on each circuit would prevent nuisance tripping on all the other circuits from a shared RCD anyway. A washing machine especially deserves its own. I assume single RCDs won't cost any more than this ebay example.

Justin, when the lights are doubled up, make sure you put them on the 10A c/b.

As for those rcd's, I wouldn't trust homebrand stuff, particularly at those prices. Trust me on this one, I replace quite a few no name rcd's, buy reputable brands.

Originally Posted by bee utey

After looking at your board, RCDs on each circuit would prevent nuisance tripping on all the other circuits from a shared RCD anyway. A washing machine especially deserves its own. I assume single RCDs won't cost any more than this ebay example.

You're saying ditch the 2x 40A RCD's and just use all RCD's instead of CB's? Which would give me space for a new shed circuit too?

BTW, we've never had a CB/RCD trip at all in the house. We've been here 6 months. So I'm not overly worried about a shared RCD for that reason, but if replacing all the CB's with RCD's is an overall better solution (best practice?), then I'm happy to go in that direction.

Originally Posted by bee utey

After looking at your board, RCDs on each circuit would prevent nuisance tripping on all the other circuits from a shared RCD anyway. A washing machine especially deserves its own. I assume single RCDs won't cost any more than this ebay example.

Single pole decent RCBO's are $30-$35 each +GST, similar to 2 pole, but you need lots more

As said, just join 2 light cct's and bang in 32A CB

You don't need 10mm unless you are pulling some SERIOUS amps(or long distance), over and above what almost anyone would do in a home workshop

Stop overthinking it

Oh, ebay RCBO's, push the test button under load and the smoke comes out, there is a sparky from Moe, that advertises in the local rag, fitting them everywhere....absolute rubbish

Originally Posted by Judo

You're saying ditch the 2x 40A RCD's and just use all RCD's instead of CB's? Which would give me space for a new shed circuit too?

That's what the sparkie who wired my solar in 2008 told me, except he couldn't get them cheap at the time.

Originally Posted by Judo

BTW, we've never had a CB/RCD trip at all in the house. We've been here 6 months. So I'm not overly worried about a shared RCD for that reason, but if replacing all the CB's with RCD's is an overall better solution (best practice?), then I'm happy to go in that direction.

I've lived in the same house for 19 years (had it 90% rewired when we moved in) and the RCD's have tripped perhaps 10 times. But when they did they didn't cause other appliances to go out with them. Example: wife puts on the washing machine, the drain pump leaks, trips the RCD but the fridge, freezer and entertainment stay on. I've currently got 4 RCDs with a max of 3 breakers on each, would go all RCDs if I redid the system. The two work sheds especially have their own.