Discuss Ze on a SWA in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

N

nicsin02

Hi guys, i am testing a 3-phase D/B tomorrow and its supply is only a 4-core cable so its earth comes from the Gland-frying pand and then a flying lead to the earth bar, normally doing domestic property i would disconnect earth for Ze ensuring no parralell paths, what would be the norm on this occasion? thanks guys
 
same procedure but measure o each of the phases. reconnect earthing conductor for PFC reading. ensure installation is isolated before dissing earth. if it's a sub-board, the EFLI is noted as Zdb
 
so do i have to take the lock-nut off and disconnect the gland to make sure no paralell paths?
 
is the SWA glanded into a metal CU or an insulated one?
 
just remove any bonding cables.... and clip on to rail.... f its a PIR put it down as a limitation...!

if you take gland off and damage it putting it back on or damage teh strands it will be hell to fix..!
 
in that case, i would disconnect any bonding conductors and the fly lead. i might get shot down , but i would prefer that to the possible risk of compromising the integrity of the glanding by disconnecting . apart from the risk of having 3 live phases flopping about unglanded.

- - - Updated - - -

beaten to it by torpedo fingers. GRRRR>
 
must be getting old. bloody heart attack slowed me down. making a good recovery now i'm back on a few beers, though.
 
If this is a swa feed would this mean it is a sub-board or a feed from a switched fuse as in both cases its not a Ze but a Zdb (Zs).
Its not normal to have a swa feed in the usual sense of a supply without it going through another device.
 
yeah its a sub mains fed from another board, i know its a Zdb but would still have to fill it in the Ze section for the new sub board or am i wrong lol?
 
yeah its a sub mains fed from another board, i know its a Zdb but would still have to fill it in the Ze section for the new sub board or am i wrong lol?
No you are correct but this is downstream from the mains so no need to remove any earthing just isolate before testing.
 
yeah its a sub mains fed from another board, i know its a Zdb but would still have to fill it in the Ze section for the new sub board or am i wrong lol?

Actually, you're wrong.:smile:

It's Zs of the sub-main and you don't disconnect anything to measure it.

The only place you measure Ze is at the origin of the installation - and for this you disconnect the 'Earthing Conductor'.

What you are talking about disconnecting is the CPC of the SWA (Sub-main)..........and for a Zs measurement this is left connected.

If, on the other hand, your 3 phase board had it's own 'earthing system' (e.g. a seperate earth rod), then you could treat it as a seperate installation, with it's own origin and 'earthing conductor'..........then you could measure Ze at your board.
 
Actually, you're wrong.:smile:

It's Zs of the sub-main and you don't disconnect anything to measure it.

The only place you measure Ze is at the origin of the installation - and for this you disconnect the 'Earthing Conductor'.

What you are talking about disconnecting is the CPC of the SWA (Sub-main)..........and for a Zs measurement this is left connected.

If, on the other hand, your 3 phase board had it's own 'earthing system' (e.g. a seperate earth rod), then you could treat it as a seperate installation, with it's own origin and 'earthing conductor'..........then you could measure Ze at your board.

Completely agree, you will be measuring nothing but the Zs at a sub-distribution board.

At the main incoming position of that sub-board, your value can be stated as Zdb, and can be noted no doubt in the Ze position of your certificate for this sub-board, with a an explanation in the remarks column. The rest of the sub-boards circuits, will again be tested as normal for Zs values.....
 

Reply to Ze on a SWA in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock