Caravan hook up

Good afternoon, thank you for everyone's posts. I really do understand this but caravans on sites hook ups are earth roded. But caravans are not from the hook up to the caravan. So for 100% protection caravans should have an earth rod fitted and connected to its chassis to make it safe at its parked postion in a field. Not just at the site hook up point

Nothing's ever 100% safe. With TT systems the RCD is the weak point - research has showed that something like 7% of installed RCDs won't trip properly when required to (either not tripping at all, or too slowly). Earthing alone - without disconnection (at least with the sort of impedances a simple rod can offer) - doesn't provide foolproof safety.


Normally we say safety is adequate if two separate faults have to occur before danger arises - say a broken c.p.c. and an insulation failure, or (in the case of double insulated equipment) two separate insulation failures. Within an installation, a broken c.p.c. doesn't of itself give rise to danger - as long as there isn't also an insulation failure - the system is still unable to give anyone a lethal shock. On that score the approach for caravans is the same as for anything else - unless there's an expectation of high protective conductor currents a single c.p.c. or means of earthing is deemed adequate.


In fact not all caravan hook-up points have their own earth electrode (rod) - it's commonly done that way as that allows PME earthing to be used for the distribution cables and so avoids the complexity, cost and possibly reliability issues that can go with having multiple tiers of RCDs that would be needed for TT distribution. But where the distribution system is TT anyway (e.g. because it's fed from an Agricultural site or difficulties keeping earthing systems separate - e.g. where metallic piped services are used for static vans) then the hookup points can use the installation's earth facility with no extra rods are needed at each hookup. Very occasionally where it can be guaranteed that the earthing system is pure TN-S (say on a large site with its own transformer) caravans can be supplied from the main earthing system with no consumer's rods at all.


   - Andy.

Good afternoon, thank you for everyone's posts. I really do understand this but caravans on sites hook ups are earth roded. But caravans are not from the hook up to the caravan. So for 100% protection caravans should have an earth rod fitted and connected to its chassis to make it safe at its parked postion in a field. Not just at the site hook up point

Nothing's ever 100% safe. With TT systems the RCD is the weak point - research has showed that something like 7% of installed RCDs won't trip properly when required to (either not tripping at all, or too slowly). Earthing alone - without disconnection (at least with the sort of impedances a simple rod can offer) - doesn't provide foolproof safety.


Normally we say safety is adequate if two separate faults have to occur before danger arises - say a broken c.p.c. and an insulation failure, or (in the case of double insulated equipment) two separate insulation failures. Within an installation, a broken c.p.c. doesn't of itself give rise to danger - as long as there isn't also an insulation failure - the system is still unable to give anyone a lethal shock. On that score the approach for caravans is the same as for anything else - unless there's an expectation of high protective conductor currents a single c.p.c. or means of earthing is deemed adequate.


In fact not all caravan hook-up points have their own earth electrode (rod) - it's commonly done that way as that allows PME earthing to be used for the distribution cables and so avoids the complexity, cost and possibly reliability issues that can go with having multiple tiers of RCDs that would be needed for TT distribution. But where the distribution system is TT anyway (e.g. because it's fed from an Agricultural site or difficulties keeping earthing systems separate - e.g. where metallic piped services are used for static vans) then the hookup points can use the installation's earth facility with no extra rods are needed at each hookup. Very occasionally where it can be guaranteed that the earthing system is pure TN-S (say on a large site with its own transformer) caravans can be supplied from the main earthing system with no consumer's rods at all.


   - Andy.