Earth Blocks and Bonding cable underneath kitchen concrete floor

[tomodo]

Hi couple of questions, in the middle of doing a CU change, was thinking to run Bonding cable under kitchen floor to CU, As its a earth cable does it require any protection such as metal conduit ? was going to chase on concrete floor about 3 meters. And doing earth connections next to CU i have ordered a Earth block, is it required to be in a insulated housing? surely it could become live in the event of a fault? cheers

 

[Pete999]

Do you have a copy of BS7671? all the info you require is in there somewhere.

 

[HandySparks]

Hi couple of questions, in the middle of doing a CU change, was thinking to run Bonding cable under kitchen floor to CU, As its a earth cable does it require any protection such as metal conduit ? was going to chase on concrete floor about 3 meters.

No, although putting it in some sort of conduit would make changing it in the future easier, if required.

And doing earth connections next to CU i have ordered a Earth block, is it required to be in a insulated housing? surely it could become live in the event of a fault? cheers

No need for an insulated housing. You're not going to enclose whatever the bonding cable is connected to, are you?

 

[davesparks]

And doing earth connections next to CU i have ordered a Earth block, is it required to be in a insulated housing? surely it could become live in the event of a fault? cheers

Just think about that for a minute and consider conduit, trunking, micc, the bonded extraneous parts, cable tray, ladder etc etc

Then if you still want me to answer that question, put a tin hat on!

 

[hightower]

Earthed metal conduit for your earth. Now that's a novel idea.

(I know op didn't say that, just a daft thought that popped in my head)

 

[davesparks]

Earthed metal conduit for your earth. Now that's a novel idea.

(I know op didn't say that, just a daft thought that popped in my head)

But would it be acceptable to dispense with the earth and just use the steel conduit as a bonding conductor?
(Just a little something to get a trainees brain turning)

 

[hightower]

I've not got my books to hand but I'd stab a guess that it should OK provided the csa is large enough, and I believe (top of head) it would have to be minimum of 25mm, so chances are unless you're running the next channel tunnel, the answer would be no?

 

[tomodo]

lol thanks for the replys , maybe being over cautious but do i then have to earth the metal conduit?

 

[davesparks]

I've not got my books to hand but I'd stab a guess that it should OK provided the csa is large enough, and I believe (top of head) it would have to be minimum of 25mm, so chances are unless you're running the next channel tunnel, the answer would be no?

Without any books that's a good effort [emoji106]

To be honest I couldn't give a definitive answer in this case without consulting the books.

But you are right that it could be used if the csa is appropriate, so you would need a steel csa of 85mm to replace a copper csa of 10mm.
This calculation is only for bonding conductors, not for cpc's.
The steel conductor needs to have the same conductance as the required copper csa. Copper has a conductance approximately 8.5 times that of steel. So to convert copper csa to steel csa for main bonds you multiply by 8.5

 

[7029 dave]

No you do not need to use this type of block.

 

[Simonslimline]

I've not got my books to hand but I'd stab a guess that it should OK provided the csa is large enough, and I believe (top of head) it would have to be minimum of 25mm, so chances are unless you're running the next channel tunnel, the answer would be no?

544.1.1

 

[LeeH]

If you're a spark, my cocks a kipper.

 

[Pete999]

If you're a spark, my cocks a kipper.

Or a Bloater as we say down in the west

 

[Brightspark2]

if you're a spark, my cocks a kipper.

lol!....

 

[Barrie Patrick]

If you're a spark, my cocks a kipper.

Does it smell Fishy then? :rofl:

 

[telectrix]

Does it smell Fishy then? :rofl:

only if he has a poor connection.

 

[hightower]

You lot could turn the talk of doggy day care to brothels in Prague in an instant.


I love it haha