IR testing sensitive equipment

[Matt07]

Been having an argument over insulation resistance testing on ballasts with an 'experienced' electrician I work with and he is saying line-earth IR tests on a circuit with ballasts will always give you dead shorts. I don't understand how this is correct surely a line to earth test wouldn't affect switch gear and should only show shorts on line to neutral?

 

[PEG]

Hi dude,are these electronic,resistor or reactive ballasts? What are they used in conjunction with? ....And why would an experienced electrician use the phrase "dead short",in this instance :icon12:

 

[Marvo]

If they're electronic ballasts they have internal surge arrestors which start conducting to earth when there's high voltages on the L or the N so they would appear to be low insulation during an IR test depending what test voltage was used. If they're wire wound inductive type ballasts they should pass a standard IR test with flying colours.

 

[Darkwood]

Its a shame this experienced Electrician didn't explain why this might occur, hope he's not your mentor or I don't see you learning anything from him - just been told it is or isn't!

 

[shanky887614]

instead of arguing with them why not ask him why he thinks that?

 

[Matt07]

I use the term arguing loosely I asked how it would work and he just said well of course it would... Tried having a bit of a technical discussion and that's all he came out with. Well I'm fresh out of college but mainly did my time with a domestic company. So my experience is limited. So to over come an electronic ballast would you do combined line neutral to earth or would you still get funny readings on them? Thanks to all for your help by the way

 

[Farmelectrics]

if in doubt ir at 230v first and if reading is ok ir at 500v

 

[Marvo]

So to over come an electronic ballast would you do combined line neutral to earth or would you still get funny readings on them? Thanks to all for your help by the way

Nope, that won't have any effect on the readings due to surge arrestors but you should always have the L+N combined for anything electronic to prevent damage to the circuitry.

 

[Matt07]

Okay ideal cheers

 

[uksparks]

Whack it with a 1000v, it usuallysles the sensitive stuff non sensitive.