Insulation Resistance testing

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Hello Thomo27...

I am just going to add my observations onto this thread a bit as-well..

Just been reading through... one or two bits still need confirming bit to open ended and as KME quite rightly said earlier..

for the moment ignore the RCD ("problem")

Verify the ring circuit readings are all acceptable first..

or you will be doin a wee-wee in the wind (as they say!!)

You question the difference between Ins Res on Rings / Radials.

Fundamentally there is no difference, other than that the far end of the circuit comes back to the CU.

When you have done you're tests are ALL of the conductors disconnected from the CU?

i.e. you have two T&E cables loose at the CU, six conductors,

2 x live

2 x neutral

2 x earth.

Personally I would step back and re-test all your readings again..

with cables open as above

1/

verify continuity, L-L, N-N, & E-E.

2/

check there are no parallel paths back to the CU bus-bars.

Switch whole installation OFF (main switch),

with Low Resistance meter

go through and test each of your L, N, E cable ends

for any direct continuity back to the CU L, N & E bus-bars?

do the same again with Ins Res to verify No high res path.

3/

With one end of your ring cable all open circuit, (not touching anything),

with meter still on low resistance scale.. and using other end of ring cable

check for any direct path between, L-E, N-E & L-N.

Then check the above again with Insulation res tester..

EVERY SINGLE ONE OF THE ABOVE TEST READINGS SHOULD BE HIGH OR OFF THE SCALE!!!

Note any low readings and tell us what you got??

 

[kme]

Hi KME when you ask 'Have you taken a purely resistive reading, to ascertain the ACTUAL resistance?If so, what was the result??

Am I right in saying you are refering to continuity results ?

If so Yes I have done continuity tests and the results were between 0.1-0.2 I cant remember the exact figure though but they didn't alarm me.

Im not going to be able to test for another weeks or so now , however I will give it another go and come back to the thread.

KME you also asked 'Just a thought. Connect up to do Ins. test, but ACTUALLY do low. impedance test (i.e. continuity.) If there is a load of any size, it should read on there ( <=2K ).

Follow me??'

Is this in the same way as you would link an outgoing p/n to an incoming p/n and then take a reading from the remaining p/n 's

No, it isn`t mate. Basically, I was asking the same question both times.........

disconnect the ring from the C.U, and seperate all the ends (2 of each P/N/E.)

From your post, I understand your insulation readings P/N are 0.00.

Which, as your meter is looking at Megohms, means "less than 10K ohms". It DOESN`T mean 0.00 ohms. So, do an "insulation test" with a low resistance meter (0-2000 ohms). You`ll either get a reading of the EXACT resistance on the circuit; or an over-range indication. If its over range, use a multimeter, which will bridge the "gap" in resistance measurement, from 2K-10K. Again, you`re taking a resitance between P & N, at ONE end of the ring, while the other end is completely "open-circuit".

NOW do you know what I mean?? ?:|