6mm Main Earth

E.E.I · Oct 7, 2015

TNC-S system
60A BS1361 Fuse
16mm Tails
6mm Main Earth
6mm Bonding

Ze 0.30
PFC 0.9kA

So if the CSA meets the requirements of 543.1.3

s= sq route of I2t/k

Sq route ((900x900)x0.1)/115

I got the 0.1 from table 3A1 pg 319, looking at the graph it looks like its about 750A to blow in 0.1 but to stay safe say 800A.

s = 2.47mm.

does that sound ok?

would you say the 6 mm is adequate?

davesparks · Oct 7, 2015

It's unusual to see a 60A TNCS supply!

If it's an existing installation and there are no signs of thermal stress to either the earthing conductor or main bonds then it is not a problem.
For a new installation it may not be acceptable if it is a PME connection due to the minimum 10mm requirement.

E.E.I · Oct 7, 2015

Would you code it in an EICR? even though it meets 543.1.3.

davesparks · Oct 7, 2015

If it is a PME supply I would record an observation with no code attached of the bonds and EC are in good condition.
If it's not PME then it's fine

E.E.I · Oct 7, 2015

No PME sticker and different results for pefc and pssc, would you say no pme?

davesparks · Oct 7, 2015

E.E.I said:
No PME sticker and different results for pefc and pssc, would you say no pme?

That suggests that it's not TNCS

E.E.I · Oct 7, 2015

davesparks said:
That suggests that it's not TNCS

yes you are correct there. my bad!

and yes it is defiantly tncs

davesparks · Oct 7, 2015

E.E.I said:
yes you are correct there. my bad!

and yes it is defiantly tncs

How do you know that it's TNCS?

E.E.I · Oct 7, 2015

by looking at the service head, earth cables connect into service head with the neutral

Ze of 0.30 would also suggest

davesparks · Oct 7, 2015

E.E.I said:
by looking at the service head, earth cables connect into service head with the neutral

Ze of 0.30 would also suggest

That doesn't tally with the differing PEFC and PSCC though.

Have you got a picture?

E.E.I · Oct 7, 2015

sorry no pic

difference was 0.10,

davesparks · Oct 7, 2015

0.10 what? Amps, kiloAmps, elephants?

Simonslimline · Oct 7, 2015

E.E.I said:
by looking at the service head, earth cables connect into service head with the neutral

Ze of 0.30 would also suggest

Is it definitely connected or does it just go in to an earth block in the side of the cutout?

The earth block may not be connected to the neutral.

What is the supply cable?

E.E.I · Oct 7, 2015

0.10kA

E.E.I · Oct 7, 2015

simon it was a concentric cable supplying the property

6mm Main Earth

E.E.I

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davesparks

E.E.I

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davesparks

E.E.I

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davesparks

E.E.I

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davesparks

E.E.I

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davesparks

E.E.I

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davesparks

Simonslimline

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E.E.I

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E.E.I

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