open PEN protection.

[sheppertonspark]

Would any fellow electricians consider using an open PEN device to protect a metal trailer used as a "Canteen". It is likely to be often connected to TNCS (forbidden by 717.411.4) and placed on concrete which makes the use of TT and rod impossible. I can draw similarity to an EV charge point with open PEN limiting the touch voltage on the car it's charging. Is this a viable option or am I missing an obvious danger that this might create. My thinking is that the user of the trailer will not be concerned with the type of supply and would connect regardless.
Your comments and thoughts would be most welcome.
I asked the Technical helpline of my registration body and got 2 different answers, this was obviously really unhelpful !!

 

[Rockingit]

Interesting. First things first - a common misconception is that you need to have an earth rod adjacent, you don't - it could be a distance away so consider if a 'remote' rod and cable run (adiabatic ahoy!) might overcome this by conventional methods first before going off-piste.

If you're still stuck, then engineering principles take over and BS7671 makes allowance for using 'new' technology or alternative methods to achieve at least the same degree of safety. However, first consider whether by bonding the trailer in the first place (which I assume is what you're getting at) if you're potentially creating a danger via introducing an earth path where none previously existed - only you know what you're looking at.

 

[westward10]

Is this trailer now a permanent fixture?

 

[westward10]

These open PEN devices have been specifically designed for EVSE to overcome the difficulties of implementing safe TT systems derived from PME sources which can include TN-S, it requires more consideration that just banging an electrode in. Personally I would not consider it.