Evaluating the risk is tricky. Many have commented that voltages tend to swing about wildly during an open PEN event, so if the o-pen device latches off once the supply has once gone out of bounds and needs a manual reset once everything is back to normal, it's likely to be a lot safer than one that reconnects as soon as the supply appears to be back within tolerances. Likewise some models have additional c.p.c. current monitoring and will trip if it exceeds 30mA, so again giving an additional layer of protection. Unfortunately these kind of details don't appear to be stipulated by BS 7671 (or the illusive equipment standard) - so it's a matter of seeing what each manufacturer offers.

From what I've seen, charge points with in-built open-pen detection are more expensive than ones without, so if you have a few there may come a point where one upstream 3-phase detector and cheaper charge-points works out cheaper.

It's always a difficult argument, if a risk is acceptable in one situation (because technicalities make better solutions impractical), why should the same risk not also be acceptable in another situation (even if lower risk, if more expensive, solutions are technically possible). It's always somewhere between doing the best we can vs enough is enough, and what level of risk is acceptable to society in general seems to be rapidly moving goal posts. I don't envy those who write the standards like BS 7671 in that kind of situation. For the rest of us, I guess if we comply with the letter of the current regs, we shouldn't have to loose too much sleep.

           - Andy.

Evaluating the risk is tricky. Many have commented that voltages tend to swing about wildly during an open PEN event, so if the o-pen device latches off once the supply has once gone out of bounds and needs a manual reset once everything is back to normal, it's likely to be a lot safer than one that reconnects as soon as the supply appears to be back within tolerances. Likewise some models have additional c.p.c. current monitoring and will trip if it exceeds 30mA, so again giving an additional layer of protection. Unfortunately these kind of details don't appear to be stipulated by BS 7671 (or the illusive equipment standard) - so it's a matter of seeing what each manufacturer offers.

From what I've seen, charge points with in-built open-pen detection are more expensive than ones without, so if you have a few there may come a point where one upstream 3-phase detector and cheaper charge-points works out cheaper.

It's always a difficult argument, if a risk is acceptable in one situation (because technicalities make better solutions impractical), why should the same risk not also be acceptable in another situation (even if lower risk, if more expensive, solutions are technically possible). It's always somewhere between doing the best we can vs enough is enough, and what level of risk is acceptable to society in general seems to be rapidly moving goal posts. I don't envy those who write the standards like BS 7671 in that kind of situation. For the rest of us, I guess if we comply with the letter of the current regs, we shouldn't have to loose too much sleep.

           - Andy.