IR test bellow 1Meg

230V/1000Ω = 0.23A (=230mA) not 0.23mA


As for how much danger readings below 1MΩ suggest - it rather depends on the situation. Not only on how much current is likely to be escaping, but also where it's going and what other sort of damage a low reading might suggest.


1MΩ is pretty arbitrary - the actual figure and now much of the installation the figure applies to has changed hugely over the years - and in an even in BS 7671 only applies to new work (rather than EICRs). In many situations 1MΩ would be ridiculously low for a satisfactory installation (say a reasonably small modern PVC/PVC system with no connected appliances) - and figures many times that should really be treated with caution. For other systems (say old damp pyro) 1MΩ would be quite optimistic and much lower values might be considered satisfactory. Some appliances can have quite low IR values - some e.g. traditional cookers - may well have a lower values than the entire rest of the installation.


Leakage from within a pyro or SWA installation with metal clad equipment, all solidly earthed, is much less of a safety problem than the same leakage that's escaping to unearthed surfaces that people could touch.


As for this pump, 1kΩ though is VERY low. 230mA going the wrong way could be lethal (and no, conventional fuses or circuit breakers wouldn't stop that either - but  RCDs might, although you shouldn't really be relying on them). Presuming it's not a huge industrial pump, I presume water has got past the seals and the pump isn't going to last very long if left neglected any longer.


   - Andy.

230V/1000Ω = 0.23A (=230mA) not 0.23mA


As for how much danger readings below 1MΩ suggest - it rather depends on the situation. Not only on how much current is likely to be escaping, but also where it's going and what other sort of damage a low reading might suggest.


1MΩ is pretty arbitrary - the actual figure and now much of the installation the figure applies to has changed hugely over the years - and in an even in BS 7671 only applies to new work (rather than EICRs). In many situations 1MΩ would be ridiculously low for a satisfactory installation (say a reasonably small modern PVC/PVC system with no connected appliances) - and figures many times that should really be treated with caution. For other systems (say old damp pyro) 1MΩ would be quite optimistic and much lower values might be considered satisfactory. Some appliances can have quite low IR values - some e.g. traditional cookers - may well have a lower values than the entire rest of the installation.


Leakage from within a pyro or SWA installation with metal clad equipment, all solidly earthed, is much less of a safety problem than the same leakage that's escaping to unearthed surfaces that people could touch.


As for this pump, 1kΩ though is VERY low. 230mA going the wrong way could be lethal (and no, conventional fuses or circuit breakers wouldn't stop that either - but  RCDs might, although you shouldn't really be relying on them). Presuming it's not a huge industrial pump, I presume water has got past the seals and the pump isn't going to last very long if left neglected any longer.


   - Andy.