PAT Testing

paul161201 · Dec 19, 2010

I was asked in my previous employment to carry out a pat test on a few 100 items. I notice often that items will fail on Continuity and Insulation Resistance.
I believe due to things like motor winding in fans and neon indicator lights.
So how would you pat test an item with a neon indicator light which is wire in parallel for Insulation Resistance?

sparx24 · Dec 19, 2010

no class 1 item should ever fail on earth continuity reading since there won't be one!
class 2 items earth continuity should be unambiguous, either very low or fail!
Insulation tests should in most cases be between earth and L+N together thus not affecting neons etc. also not risking damage to electronics.
How would you be able to test IR between L&N on anything except extension leads, unplugged IEC (kettle type) leads.
The main items that will give low IR's between both lines and earth are things with PI network filters eg, washing machines, fridges, PC's.
Only problem I have found is with Chinese imported desk fans with 3 core flex but no earthed /exposed metal work to test to!

i=p/u · Dec 19, 2010

100mA test known as soft test

Jurasic Spark · Dec 19, 2010

sparx24 said:
no class 1 item should ever fail on earth continuity reading since there won't be one!
class 2 items earth continuity should be unambiguous, either very low or fail!
Insulation tests should in most cases be between earth and L+N together thus not affecting neons etc. also not risking damage to electronics.
How would you be able to test IR between L&N on anything except extension leads, unplugged IEC (kettle type) leads.
The main items that will give low IR's between both lines and earth are things with PI network filters eg, washing machines, fridges, PC's.
Only problem I have found is with Chinese imported desk fans with 3 core flex but no earthed /exposed metal work to test to!

Wrong way round ???

sparx24 · Dec 20, 2010

yus Jurasic OOPS! swopped them when decided not to write it as class II/I but as 2/1 but typo'ed it in so doing!!!
Should have left it as it was as II looks like double insulated symbol anyway.
Well spotted. sorry to O.P.

accordfire · Dec 20, 2010

sparx24 said:
no class 1 item should ever fail on earth continuity reading since there won't be one!
class 2 items earth continuity should be unambiguous, either very low or fail!

Are you sure?

I'd like to hope that's t'other way around.........

Class 1 is all that metal stuff with "Class 1 - This device must be earthed" all over it......

Class 2 is all the plastic double insulated stuff.

accordfire · Dec 20, 2010

paul161201 said:
I was asked in my previous employment to carry out a pat test on a few 100 items. I notice often that items will fail on Continuity and Insulation Resistance.
I believe due to things like motor winding in fans and neon indicator lights.
So how would you pat test an item with a neon indicator light which is wire in parallel for Insulation Resistance?

Neons won't make any difference to an insulation test - when the tester shorts out the L-N it provides a low/no resistance path, and the neon is effectively ignored.

Never noticed a problem with fans either.

What are you PAT testing with?