No bonding on new build

[PBC_1966]

Which is exactly why some people recomend sticking a rod in.

And why as noted way up the thread, in other jurisdictions an earth electrode is required. During normal operation it reduces the (small) difference in potential caused by voltage drop on the neutral, and in the event of an open neutral, it at least helps to keep the voltage down (the exact level depending upon the electrode resistance, resistance of loads in use at the time of failure, etc.).

 

[spinlondon]

I thought it just equalised any potential difference between your earthing and the massive earth.

 

[Andy™]

but thats 'dangerous'

 

[ianmacd]

The rods are on the pen conductor on a pme network NOT in someones house attached directly to the met.

 

[Andy™]

so what if DNO installs a rod directly under service head connected to neutral? and then you connect a rod 2mt away connected to PME earth. your rod dangerous, their rod safe?

as has already been mentioned, metallic services (gas & water) are often a much better earth connection than an earth rod. yet these are always bonded, but a rod is now considered dangerous?>

 

[ianmacd]

Well if you install a rod on a tncs system then I would be looking at the whole installation as if you can make a fundamental mistake like that, what else have you bodged?

 

[Andy™]

Well if you install a rod on a tncs system then I would be looking at the whole installation as if you can make a fundamental mistake like that, what else have you bodged?

please explain this 'fundamental mistake' and how its a problem

 

[PBC_1966]

The rods are on the pen conductor on a pme network NOT in someones house attached directly to the met.

As discussed recently in another thread, in the U.S. there is always an earth electrode provided at the premises, connected to the neutral at the main distribution panel or meter.

Although it's rarely done in the U.K., there is nothing in the regs. to say it mustn't be done (and as one of the key points of another thread discusses, electrically it would be no different from bonding a metallic underground water line anyway).

 

[ianmacd]

[quote name='Andy

 

[Andy™]

and? how exactly does this make it a 'fundamental mistake' by adding a rod?

even by your own 'proof', it doesnt say your not allowed to have a rod, or that its dangerous

 

[ianmacd]

OK so what size cable would you put in between said rod and MET? I would guess you would follow the sizing for a TT system?

Also, I have never said it was dangerous electrically (assuming correctly sized conductors are used), just form the point of view that its not expected so could lead to dangerous conclusions if DNO were to withdraw their earth.

 

[Andy™]

id use one that would exceed the max current that could flow to rod.

even if you get a good reading of 5 ohms, thats still 46A, so 10mm would easily cover it

so assuming that its installed to 7671 (which by your own proof, it doesnt exclude it), then how is it a 'fundamental mistake'?

DNO would not simply remove an earth, unless it was for safety reasons (dodgy TNS connection etc)

 

[ianmacd]

[quote name='Andy

 

[Andy™]

then use the same CSA the the earthing conductor. but i fail to see how using 16mm to the rod instead of say 10 or 6, makes any difference to the safety of the installation, since even 4mm would be more than enough to cope with the load in most cases

 

[ianmacd]

[quote name='Andy

 

[spinlondon]

Regulation 542.1.8, refers to common earth conductors for multiple installations that have their own separate earthing arrangments.

How does that apply in this case, where there is only one installation?

 

[steptoe]

[quote name='Andy