Fire safety or nuisance tripping - which is more important?

You could wire it straight into the incoming meter tails, avoiding all those pesky breakers.  If the comms cabinet catches fire and burns the whole building down, at least you will know that it didn't nuisance trip.

Simon Barker said:

Fire safety or nuisance tripping - which is more important?

That depends on what the equipment being powered is doing.

What if part of multi-occupancy premises has, say medical locations ?  (Or the question might be asked of AFDD vs no AFDD for 'care homes' ... buy which I really mean 'nursing homes' and similar, but the question could be asked.) In which cases, Regulation 710.421.1.7 clearly provides the answer on the use of AFDDs for medical locations of Group 1 and Group 2, and requires a risk assessment for their use in medical locations of Group 0.

Simon Barker said:

Fire safety or nuisance tripping - which is more important?

That depends on what the equipment being powered is doing.

What if part of multi-occupancy premises has, say medical locations ?  (Or the question might be asked of AFDD vs no AFDD for 'care homes' ... buy which I really mean 'nursing homes' and similar, but the question could be asked.) In which cases, Regulation 710.421.1.7 clearly provides the answer on the use of AFDDs for medical locations of Group 1 and Group 2, and requires a risk assessment for their use in medical locations of Group 0.

Hi Graham. In response to your statement that addresses the application of Arc Fault Detection Devices in medical locations  classified as Group 1 & 2

BS 7671 indicated that AFDDs are not utilised in these locations. My inquiry pertains to whether this implies that the deployment of AFDDs in hospitals may be prone to nuisance tripping, and therefore, unlikely to provide substantial benefits in such settings ? Im focused on whether AFDDs are recognised for their propensity to nuisance trip. So I suppose, I seek to understand the rationale behind the absence of AFDD installation in medical locations classified as Group 1 & 2. Thanks 

Andrew

AMK said:

BS 7671 indicated that AFDDs are not utilised in these locations. My inquiry pertains to whether this implies that the deployment of AFDDs in hospitals may be prone to nuisance tripping, and therefore, unlikely to provide substantial benefits in such settings ?

There are a number of factors in play, as to why AFDD are not specified for medical locations. The fact that some medical electrical equipment may not fit the EMC signature is only one of them ... another is the fact that if you have a medical IT system, for example, a single fault should not remove power by operating a protective device, just like RCDs.

AMK said:

Im focused on whether AFDDs are recognised for their propensity to nuisance trip.

I have had discussions with people in the industry, to the effect that they believe some equipment that is not 'domestic and similar' (particularly for EMC environment) may cause unwanted operation of AFDDs, that I understand are constructed for 'Domestic and light industry' EMC environment.

All I have at the moment is third-party reports of this, without detailed evidence ... and I do not know if some AFDDs are more of a concern than others.