25mm SWA!!

[SparkyDips]

hello guys i overheard a conversation last week about a supply to an outbuilding which will comprise of: 45A Shower, 32A Ring Final and 6A lighting. Total demand = 83A.

outbuilding is 28Mtrs from main house and will have no extraneous conductive parts as the water feed will be plastic.

now the spark was saying that a 25mm SWA buried in the ground will need to be run and can use the house main earth.

whats your thoughts on this guys??

regards

 

[telectrix]

10mm is well adequate. the guy is talking through his arse. has he not heard of diversity?

 

[Jay Sparks]

25mm swa seems abit over the top to me. Doing a rough calc, 83A x 0.4 = 33.2A. Do some calcs and you will know what size cable you need.
Although I useally take out the biggest mcb, then add the rest, divide by 4 then add the biggest back for your total. This gives a slightly higher demand but still no need for the 25mm swa.lol

 

[telectrix]

sorry, jay. you need to allow 45A for the shower, the 0.4 of the rest. that equates to around 60A.

 

[Jay Sparks]

sorry, jay. you need to allow 45A for the shower, the 0.4 of the rest. that equates to around 60A.

Cheers tel, I realised what I had done and edited my post before your reply.lol

 

[SparkyDips]

so 10mm having 60A CCC and 16mm having 78A CCC more than adequate.

25mm having 99A CCC lol

 

[telectrix]

then again that shower may not pull over 40A . manufacturers are overly optimistic with their figures.

 

[SparkyDips]

yes true. i think i may suggest that 35mm "just to be safe" will be better and cheaper in the long run!! lol

 

[Jay Sparks]

I wonder which is the right way of working out demand?? I do the same by taking away the biggest mcb and adding it back to the total but I was tought to divide by 4. I know alot of lads multiply by 0.4. I suppose doing it the multiply by 0.4 way will give you a slightly higher demand and air on the side of caution!!

 

[Knobhead]

Funny how the question is always asked in the 2[SUP]nd[/SUP] inst. It’s never I think it should be what ever, but my friend thinks it should be……….

Funny old world. Or am I a cynic?

 

[i=p/u]

No diversity on shower, any specifics what else will be plugged in? Il say 60A on 63A breaker = 25mm

 

[telectrix]

a lot of confusion arises over the fact that while a MCB may be 32A for a socket circuit, say, the actual load of the circuit may never get above 20A, sometimes even a lot less if it's not a kitchen RFC.

 

[SparkyDips]

too late for calculations Tony!! Saturday night is beer time! lol

with this sort of attitude its no wonder people are put off making a post!!

 

[SparkyDips]

its not a kitchen, will be a small gym comprising treadmill and rower. with shower.

i have been doing the comms cabling and just overheard this conversation.

 

[telectrix]

No diversity on shower, any specifics what else will be plugged in? Il say 60A on 63A breaker = 25mm

you got shares in a copper mine?

 

[Jay Sparks]

you got shares in a copper mine?

7

He is probably the pikey that will be steeling it to sell for scrap.lol Sorry i=pu, only yoking.

 

[i=p/u]

Yes jay i gather it up on all jobs like a pikey i suppose.. £300 quid will buy the cable

 

[Jay Sparks]

Yes jay i gather it up on all jobs like a pikey i suppose.. £300 quid will buy the cable

Wish I had any spare cable to sell for scrap but I price my jobs up to a tee and theres never any left over!!!!lol Ha ha ha, I wish.lol

 

[SparkyDips]

Wish I had any spare cable to sell for scrap but I price my jobs up to a tee and theres never any left over!!!!lol Ha ha ha, I wish.lol

hmm i've still got 5Mtrs leftover???

 

[i=p/u]

We on big site at moment and full of scrap metal, copper boilers the size of a small car. Mmmmm, the plumbers are at it.

I said what's that boiler lying in bushes for, they said the boss is taking it, the boss came back to lift there rubble and they didn't mention it and piled all rubble away from it at bottom of path, crafty buggers.