Code For .....

[Electroglow]

Hello just wondered what your thoughts are on the main earth to a single phase tns cu being 10mm. Incoming tails 16'mm twin and earth.

Protected by rcd and 60a switch fuse.

Bonding to water 16mm... And before you say I have then the wrong way round I don't. Lol... Earth in t and e being used.

Total load on cu probably 20ish amp at max ???

 

[binky]

don't see a problem from what you describe

 

[Electroglow]

I always upgrade the earth to 16mm. Tns. I know we can get away with 10mm but I stil think I c3 for upgrading?? Requires improvement

 

[Electroglow]

Oh ye and ..... Distance is around 20m away from dno. No rcd protection on the 16mm t and e.

 

[binky]

why? 20A load, installer proably only used 16mm becuase wholesalers don't stock 6 and 10mm tails these days. 16/10 combination is compliant with regs. no harm in bigger earth, but not required.

 

[binky]

Oh ye and ..... Distance is around 20m away from dno. No rcd protection on the 16mm t and e.

does it need RCD???

 

[Electroglow]

I would have said so. Travels through stud walls ect. I always use SWA to sub board at a distance. Again not a fail tho still a improvement

 

[NozSpark]

Do you mean through stud walls or within stud walls,,,, there is quite a difference!

 

[Electroglow]

I mean with in.

 

[NozSpark]

does it need RCD???

+1

This would all depend on when it was installed,,,, our regs are not retrospective

 

[SLIPSHOD & SLAPDASH]

Are you sure its a 10mm Cpc. 16mm Tw&e normally has a 6mm Cpc !

 

[kerching]

Are you sure its a 10mm Cpc. 16mm Tw&e normally has a 6mm Cpc !

Ah, you beat me to it

 

[Electroglow]

This is where I get a lil confused. So what If it was installed about 10 years ago. it's still a reccomedation. We test to the regs now not 10 20 years ago. If that was the case every instal is fine

 

[SLIPSHOD & SLAPDASH]

This is where I get a lil confused. So what If it was installed about 10 years ago. it's still a reccomedation. We test to the regs now not 10 20 years ago. If that was the case every instal is fine

Doesn't matter because its probably a 6mm cpc. You will have to do the adiabatic equation to determine if the earth is acceptable

 

[Apache]

This is where I get a lil confused. So what If it was installed about 10 years ago. it's still a reccomedation. We test to the regs now not 10 20 years ago. If that was the case every instal is fine

No - the regulations are NOT retrospective.

 

[binky]

you have a switch fuse 63A - so does 16mm FTE comply? In your defence this is a poorly explained subject and doesn't sit well in my mind, but in short, beyond the Switch fuse it's just a 63a circuit. What you are looking at is actually standard practice, but it's not obvious....and doesn't feel right.

 

[steptoe]

6mm on a 63a is standard practice earthing where exactly binky?

 

[Electroglow]

Don't really understand what binks is on about.. Doest feel right ect lol. As I have said it rare to see a earth so low in size with 16mm or 25mm tails. All I ask was what do I think the code would be. That was all.

 

[steptoe]

You need to calc it to find out if it complies or not before you can code it.

 

[binky]

Don't really understand what binks is on about.. Doest feel right ect lol. As I have said it rare to see a earth so low in size with 16mm or 25mm tails. All I ask was what do I think the code would be. That was all.

I gathered that 10mm earth is adequte for 16mm tails. Once you hit switch fuse CPC of FTE is sized correctly for cable, ergo you don't need a bigger earth and hence there is no code because it is compliant, though as Steps says you should calculate to prove point. Just seems daft to feed 10mm earth then connect up a 6mm. For a 20A load I would rather feed in 6 or 10mm tails (and reduce fuse in switch fuse to boot), but these aren't widely available any more, so most people use 16mm becuase that is easy to get