Taking Zs At Light Switch

[r.b]

I have a metrel mi 3100 im going round doing the repairs that a tester has found one is high zs at light switch mines a 3 probe line ,neutral and earth Im ok with sockets ,pendants,how do I test zs at a switch with line and earth there?Or cant I?I have thought about clipping earth and neutral probes together and putting this on earth and brown probe on line will this take the reading like that?

 

[binky]

don't know about metrel, but you could always do R1+R2

 

[Evans Electric]

Could give it a try r.b      take the R1+R2      then try your N+E leads together at the switch.

 

[batty]

Problems I can see if circuit is RCD protected its possible the Rcd will go before the test is done. Also is your meter capable of doing this test?

 

[r.b]

how do i get the high reading down ?put a new switch on sometimes lowers it

 

[binky]

high readings are generally caused by poor connections, could be at the switch or further down the circuit - testing will reveal!! tweak something, test again, keep tweaking things until reading changes, then you know you have found the issue (might be more than one)

 

[Steve3948]

What was your High reading then ??

 

[Sharpend]

I think Megger do a two lead tester for Zs. Perhaps this is what the guy has used when doing report?

 

[r.b]

yes this is what the guy probly used a just ad a go of mine joining earth and neutral together it dnt work tripped a dual rcd board on a zs rcd setting

thing is all i can do is test at lights!Al tighten up switches

 

[SLIPSHOD & SLAPDASH]

Use  a long lead to connect the N to any N on that rcd. The neutral is only to make the meter work and wont affect the test.  Is there an earth cable or is the conduit, swa etc the cpc  ?

 

[r.b]

A tested a switch tonight at my house just trying it,the houses on where I am testing are no rcd

 

[Steve3948]

My old Metrel MFT worked piggy backing N&E lead, this was full rated and not 1/2 so no good if Rcd is in circuit.

 

[SLIPSHOD & SLAPDASH]

I have done the same many times with a Fluke 1652, not sure if its an approved way ?

 

[r.b]

what so it works piggy backing on no rcd

 

[SLIPSHOD & SLAPDASH]

I suppose its not an approved way as if the earth is poor you will not get a correct reading and it could put a voltage on the cpc.

what so it works piggy backing on no rcd

 Yes, but read my comment above

 

[Steve3948]

Slips my Metrel had a banana socket on the back of the earth clip for that purpose, and it showed it in the instructions, so who knows, mind you Metrel is Polish or Russian or something.

 

[SLIPSHOD & SLAPDASH]

I have 2 Metrel easitests broke here, cant find anyone to repair them. Megger Mark thought not.  Metrel  must have a repair base (forgotten the UK company name)

 

[pewter]

I would go to the pendant and test the lighting feed and then test the switched live side with switch closed. If that showed high reading on the switched live  i would then check out the switch and pendant.

 

[r.b]

the reading was over 200 ohms the zs at light switch 

 

[steptoe]

how to do a 3wire test at a light switch,

turn switch off

ensure a normal filament lamp is in situ

Line probe to line at switch

earth probe to earth

neutral probe to switch wire at switch

test,




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