pat testing questions

"is required to have a residual operating current not exceeding 30 mA at 40 ms."

Usually the requirement for 30mA RCDs providing additional protection is something closer to 300ms at a residual current of 30mA and 40ms at 150mA.

And is the minimum ip rating ip64 or 68?

IP ratings have two parts - the first digit indicates protection from solid objects (e.g. fingers) and the second against liquids (usually water/rain).


IP6X seems a bit steep for a socket - ordinary sockets often struggle to get any higher than IP2X due to the openings needed for the plug's pins - but if it's assumed that it has a waterproof cover that's in place then IP4X would be reasonable minimum for most circumstances (in general enclosures need to meet IP4X for their top surfaces) and IP5X would be common at least for domestic outdoor sockets.


For the liquid part, it depends on the circumstances, if it's sheltered (e.g. outdoors but under cover) it might not need anything special at all, if subject to just falling rain (sheltered from side winds) then IPX3 might do - IPX4 would provide protection from water sprays from any angle which should suit most weather conditions and IPX5 would provide protection from water jets from any direction (so suitable where the worst case would be a mis-directed hosepipe). IPX8 is for long term total immersion - which seems a bit OTT for most situations where you might be wandering around with a plug in hand.


  - Andy.

"is required to have a residual operating current not exceeding 30 mA at 40 ms."

Usually the requirement for 30mA RCDs providing additional protection is something closer to 300ms at a residual current of 30mA and 40ms at 150mA.

And is the minimum ip rating ip64 or 68?

IP ratings have two parts - the first digit indicates protection from solid objects (e.g. fingers) and the second against liquids (usually water/rain).


IP6X seems a bit steep for a socket - ordinary sockets often struggle to get any higher than IP2X due to the openings needed for the plug's pins - but if it's assumed that it has a waterproof cover that's in place then IP4X would be reasonable minimum for most circumstances (in general enclosures need to meet IP4X for their top surfaces) and IP5X would be common at least for domestic outdoor sockets.


For the liquid part, it depends on the circumstances, if it's sheltered (e.g. outdoors but under cover) it might not need anything special at all, if subject to just falling rain (sheltered from side winds) then IPX3 might do - IPX4 would provide protection from water sprays from any angle which should suit most weather conditions and IPX5 would provide protection from water jets from any direction (so suitable where the worst case would be a mis-directed hosepipe). IPX8 is for long term total immersion - which seems a bit OTT for most situations where you might be wandering around with a plug in hand.


  - Andy.