O PEN Devices and Supplies

No point where the exposed-conductive-parts are within the building (i.e. inside the equipotential zone in old money) where everything should be at the same potential(ish) even during an open PEN event.

It can see them becoming an option for for other equipment outdoors in some situations - but as most other situations have shown over time to be relatively low risk, I suspect the price of O-PEN devices will have to reduce substantially before there will be much uptake. Not an option for the most obvious cases of caravans or boats of course without a change in Law (in the UK) as the ESQCR prohibits the use of PME earthing anyway.

Generally switching protective conductors has a major disadvantage - switching devices are much more prone to failure than solid joints or continuous unbroken conductors, so there's a risk of losing ADS under non-broken-PEN situations to be balanced against the (rather low) risk of broken PEN events too.

Switching bonding conductors is likely to cause as many problems as it solves. Potential differences can enter an installation from many different sources - e.g. metallic water or gas pipework common with neighbouring properties, as well as the PEN conductors and so there is probably more to be gained by keeping bonding intact rather than switching it off, even during an open PEN event. Also the required current carrying capacity of main bonding conductors in particular is always rather an unknown (especially in PME systems where currents from neighbouring properties can flow in your bonding conductors) so even picking a suitable rating for such a device would be problematic - a 10mm² solid copper bond will generally survive at lot more abuse than say a 100A switching device.

   - Andy.

No point where the exposed-conductive-parts are within the building (i.e. inside the equipotential zone in old money) where everything should be at the same potential(ish) even during an open PEN event.

It can see them becoming an option for for other equipment outdoors in some situations - but as most other situations have shown over time to be relatively low risk, I suspect the price of O-PEN devices will have to reduce substantially before there will be much uptake. Not an option for the most obvious cases of caravans or boats of course without a change in Law (in the UK) as the ESQCR prohibits the use of PME earthing anyway.

Generally switching protective conductors has a major disadvantage - switching devices are much more prone to failure than solid joints or continuous unbroken conductors, so there's a risk of losing ADS under non-broken-PEN situations to be balanced against the (rather low) risk of broken PEN events too.

Switching bonding conductors is likely to cause as many problems as it solves. Potential differences can enter an installation from many different sources - e.g. metallic water or gas pipework common with neighbouring properties, as well as the PEN conductors and so there is probably more to be gained by keeping bonding intact rather than switching it off, even during an open PEN event. Also the required current carrying capacity of main bonding conductors in particular is always rather an unknown (especially in PME systems where currents from neighbouring properties can flow in your bonding conductors) so even picking a suitable rating for such a device would be problematic - a 10mm² solid copper bond will generally survive at lot more abuse than say a 100A switching device.

   - Andy.