shed supply

[dave-gardiner]

oh no not again.
shed is 100M away. 13 A load.
plastc conduit.
mcb in house 16A type b.
6mm live and neutral thru conduit (plastic) to shed. then earth rod to make TT system and finally rcd in shed. is this ok?

 

[Marvo]

If there's no exported earth then the earth resistance reading of the spike will be critical. What was the spike readings?

 

[Golden_Boy]

If there's no exported earth then the earth resistance reading of the spike will be critical. What was the spike readings?

And the disconnection times
And PFC

 

[dave-gardiner]

no readings yet as this is a suggested design. cable sizing done from cable calcs. I could take a 6mm earth from the house but I was worried about the distance and thought a TT system would be preffered from the house pme system.

 

[Marvo]

I think a lot of the design merits boil down to your chances of getting a good stable spike reading. Maybe hedge your bets and leave a couple of draw boxes in the conduit rout so you can pull an earth later if needed.

Where I am I would always export the earth rather than a local spike. Your call, maybe your area is less hard work to get a decent reading.

 

[Octopus]

Wouldn't swa be slightly easier to install than 100m of conduit?

 

[dave-gardiner]

yes it would, but !

 

[Dan23584]

SWA would also have earthed mechanical protection.

 

[Octopus]

yes it would, but !

but ..................?

 

[Marvo]

Yeah I was waiting for the but explanation as well. SWA would be the way to go. I'm sure any extra materials expense would be offset by the fact it's quicker and easier to work with, more durable and reliable as well.

 

[Deleted member 9648]

I switched off as soon as 'shed' was mentioned.....:lipsrsealed2:

 

[Octopus]

but .... I've already installed the conduit (maybe)?

 

[IQ Electrical]

Are there any extraneous-conductive parts in the shed?

This is the most important question before deciding on using the suppliers earth or creating a local TT system.

If the answer's 'no' then I would certainly be using the suppliers earth.

 

[Engineer54]

Why on God's Earth, did you go for a conduit system, When SWA in this instance is a complete no-brainer. Even better a 3 core SWA cable!! Sorted!!!

 

[dave-gardiner]

conduit system is customers choice. he has access to it at no cost also singles at no cost. so when I mentioned swa, they said cost ! as for metal parts, the power is mainly for a freezer.