Safe isolation of rotary isolator when no incoming voltage present.

[Avo Mk8]

Fair point

You could then argue you need to prove the reference

Which you do by having the proving unit/equipment 'calibrated' (ie checked against its spec.) every so often, (generally by a calibration laboratory), the period being determined from an assessment that considers service conditions, usage, previous pre-cal results, and manufacturers recommendations.
This is standard procedure in industry, particularly for companies certified to quality standards, and they get independently audited to check they are doing it satisfactorily!

As per mainline - must cut down on my words

 

[mickegh]

Which you do by having the proving unit/equipment 'calibrated' (ie checked against its spec.) every so often, (generally by a calibration laboratory), the period being determined from an assessment that considers service conditions, usage, previous pre-cal results, and manufacturers recommendations.
This is standard procedure in industry, particularly for companies certified to quality standards, and they get independently audited to check they are doing it satisfactorily!

As per mainline - must cut down on my words

I was referring to the 2-wire testing which assumes there would be a valid reference point if testing between an energized line conductor and some other point

 

[Avo Mk8]

I was referring to the 2-wire testing which assumes there would be a valid reference point if testing between an energized line conductor and some other point

For this particular question of safe isolation in a working environment, is there philosophical difficulty in assuming the installation PE would be a valid reference?

 

[UNG]

I suppose there is an argument here for having the holy grail for some in your toolbox which is the neon screwdriver alternatively there is one of these Socket & See EPF-PRO single point testers which I have found to be very useful over the few years I've owned it

 

[James]

I suppose there is an argument here for having the holy grail for some in your toolbox which is the neon screwdriver alternatively there is one of these Socket & See EPF-PRO single point testers which I have found to be very useful over the few years I've owned it

I do keep in my work trouser pocket one of the much loved/hated “volt stick”
Devices.
As said before, NOT to be used to prove anything is live or dead, but a quick wave over a bunch of cables sometimes will make you recheck all possible sources of supply before cutting or disconnecting anything.

 

[mickegh]

Ya I looked at those Socket and See onetime . I think the threshold was 50V AC

My martindale single-point test is > 100V AC on the 2-wire voltage tester

 

[mainline]

View: https://www.youtube.com/watch?v=glsg2HpWyok