Periodic testing with the power on and all loads connected

[oracle]

I recently watched a tester and his mate do a periodic inspection and testing on a social housing dwelling without turning off the power or disconnecting any loads.
The Ze was measured without disconnecting the main earth conductor and Zs taken with the loads connected. They subtracted the dodgy Ze from the dodgy Zs and recorded these as the R1 R2's. No insulation resistance was measured and RCD was tested using the test button on it.

 

[Pete999]

I recently watched a tester and his mate do a periodic inspection and testing on a social housing dwelling without turning off the power or disconnecting any loads.
The Ze was measured without disconnecting the main earth conductor and Zs taken with the loads connected. They subtracted the dodgy Ze from the dodgy Zs and recorded these as the R1 R2's. No insulation resistance was measured and RCD was tested using the test button on it.

What was the companies name? Bodge it and Scarper, yes I l know it's old

 

[Nigel]

Could have been a limitation set by the client but I doubt it.

I have no issue with calculating R1+R2 but this practice would probably fall foul of safe working guidelines.

 

[Octopus]

And they charged how much...

This is the way EICRs will go is they are mandated

 

[Wilko]

RCD ms to trip is a mandatory test, surely?

 

[Deleted member 26818]

I take it the R1 + R2 values were recorded in the schedule for test results?

 

[westward10]

Are you surprised our industry has become shambolic free for all.

 

[oracle]

Essex I agree with you about calculations provided that the values used are valid. Ze without disconnecting the earth and Zs with the loads connected would not produce valid values

 

[Deleted member 26818]

Problem with calculating R1+R2, is what is the point?
What purpose does it serve?
It’s like writing the date as Weds 29/08/2018.
Who’s going to look at the report and care that it was done on a Wednesday?
Measure the Ze, measure the Zs, if anyone wants to know what the Zs minus the Ze equals, let them do the calculation.
Don’t put a calculated value in a schedule for test results pretending that you conducted that test when you didn’t.

 

[oracle]

It was social housing so I don't know what limitations may have been set, point is, it was a bodge job at best

 

[HappyHippyDad]

I recently watched a tester and his mate do a periodic inspection and testing on a social housing dwelling without turning off the power or disconnecting any loads.
The Ze was measured without disconnecting the main earth conductor and Zs taken with the loads connected. They subtracted the dodgy Ze from the dodgy Zs and recorded these as the R1 R2's. No insulation resistance was measured and RCD was tested using the test button on it.

So you did less than even them then?

 

[oracle]

Don't know what you mean I wasn't involved in the job merely observing the poor practice

 

[HappyHippyDad]

It was banter Oracle, nothing to take personally, hence the winking eye at the end. Sorry if it offended you.

 

[Risteard]

Problem with calculating R1+R2, is what is the point?
What purpose does it serve?
It’s like writing the date as Weds 29/08/2018.
Who’s going to look at the report and care that it was done on a Wednesday?
Measure the Ze, measure the Zs, if anyone wants to know what the Zs minus the Ze equals, let them do the calculation.
Don’t put a calculated value in a schedule for test results pretending that you conducted that test when you didn’t.

I believe dead continuity tests serve no real purpose on an installation which is already energised. These tests are for verifying that it is safe to energise. Therefore a standard agreed limitation I have is that cpc continuity will be verified through live (Zs) testing. Even GN3 recognises the validity of this approach.

The only time I might use dead continuity tests for a periodic inspection would be R2 and not (R1+R2) tests - to verify that e.g. a Class I luminaire (which might be awkward to remove and replace) was indeed earthed.

 

[Risteard]

The Ze was measured without disconnecting the main earth conductor and Zs taken with the loads connected.

If the Earthing conductor or the main protective bonding conductors are not disconnected to remove parallel paths then it is a Zs - not a Ze.

Not really sure what you mean about removing loads to Zs test.

 

[ChrisElectrical88]

This sounds like a classic job from my company. Sending apprentices around doing social housing, giving them 2 hours to test and do all remedials. 4 a day. If they send me on them I get 2 done a day with no remedials, which is the reason I rarely get sent to them.

For what it’s worth with the calculations I’ll Ze with main earth disconnected, R1+R2 and calculate the Zs with one live test at the end of line to confirm is near enough the calculated result.

 

[ChrisElectrical88]

Obviously all other tests such as IR, RCD and R2 to main bonding also taken place.

 

[Pete999]

This sounds like a classic job from my company. Sending apprentices around doing social housing, giving them 2 hours to test and do all remedials. 4 a day. If they send me on them I get 2 done a day with no remedials, which is the reason I rarely get sent to them.

For what it’s worth with the calculations I’ll Ze with main earth disconnected, R1+R2 and calculate the Zs with one live test at the end of line to confirm is near enough the calculated result.

Sounds like that's one class outfit you work for Chris. hope there is nobody else from your firm on the Forum.

 

[ChrisElectrical88]

It’s shocking mate. I’m literally here as a filler job. Leaving very soon. Quote a few dodgy big companies down here.

 

[Pete999]

It’s shocking mate. I’m literally here as a filler job. Leaving very soon. Quote a few dodgy big companies down here.

Where Delia the Chef land.