250v IR

[Clinchy]

Hey guys,

My NIC assessor told me I can apply 643.3.2 (the part near the bottom about SPD's or "other" equipment) to all circuits.

It doesn't quite feel right but would save a lot of time not having to re-arrange rooms.

Any opinions?

 

[Dartlec]

Hey guys,

My NIC assessor told me I can apply 643.3.2 (the part near the bottom about SPD's or "other" equipment) to all circuits.

It doesn't quite feel right but would save a lot of time not having to re-arrange rooms.

Any opinions?

What sort of SPDs are they?

If we're talking domestic SPD at a consumer unit, then I don't see how it would be considered 'not reasonably practicable' to disconnect them or just pull out the inserts for a test. If there are lots of SPD sockets then it would apply to all those circuits, but not those without SPD on.

What do you mean by 're-arranging rooms'?

 

[pc1966]

I can see the point, but equally 250V testing is not even matching the 358V peak AC voltage from normally working at 230V + 10% tolerance.

Usually the risk for electronics is when doing L-N testing on very low power devices like USB outlets, small LED bulbs, etc, and the IR tester is then able to charge up the internal PSU parts to around 500V, which is 40% above normal operating limits and quite likely to cause damage.

Testing L+N to E would not normally be a risk, as any filter capacitor from L-E should be of the class-Y sort (which should be OK for pulses to something like 5kV, or 1kV DC), but if you do see a low R at 500V then trying again at 250V would confirm if surge protection is present as you see a big difference (fraction Mohm at 500V, or tens of Mohm at 250V).

Also you often see DB size SPD that have a MOV (metal oxide varistor) between L & N which shows that sort of 500V/250V behaviour, but they have a GDT (gas discharge tube) from N-E and often they are completely open at 500V, but fraction M if tested at 1kV. Which you should not be doing anyway...