Exterior socket on PME system

[Midwest]

Apologies, I was just surprised at that comment.

Which one?

 

[soulman]

Achieving an Ra of 3.35

 

[happysteve]

Draw it out Steve, the N>E link is before the RCD, so current flowing down the PE will not go through the RCD causing an imbalance.

Okey dokey The squiggles inside the circle are meant to represent an RCD. In the event of a broken PEN (and no other fault), the same current passes through both poles of the RCD and there is no imbalance. The current then flows through the CPC, through the person, and to earth.


The picture below just shows that the formula A722.3 is correct.


So I still maintain that an RCD will not help in this situation.

 

[Midwest]

I'm cooking 'tea' at the mo, so not following the thread, but this vid (Pete's copyright) is often used;

 

[South Spark]

Ok long day so bear with me. Informative video but it seems to me that it only applies if there is no other path to earth than the affected person.

If the PEN is broken then would the current not flow back through the bonding to true earth especially if I introduce earth rods into the system?

Could I introduce an earth rod connected to the earth terminal in the socket?

 

[Midwest]

It's a matter of timing

 

[Des 56]

Utilise the Pme for the socket,add a rod

Don't employ any Horses,Donkeys or Cows to operate the sound system and every ones happy

 

[happysteve]

Ok long day so bear with me. Informative video but it seems to me that it only applies if there is no other path to earth than the affected person.

If the PEN is broken then would the current not flow back through the bonding to true earth especially if I introduce earth rods into the system?

Could I introduce an earth rod connected to the earth terminal in the socket?

Sorry South Spark for meandering off a bit...

Re your first question... yes it would. There has been some to-ing and fro-ing about the numbers, but essentially yes, having an earth rod would make the situation safer.

Re your second question... If you mean, "connect the earth rod to the socket and still retain the CPC from the TN-C-S" I would advise against this, unless you have 10mm earthing conductor all the way back to the MET (for the same reason that bonding needs to be 10mm). If you mean, "Run the CPC to the socket but don't connect it to the earth pin (or anything exposed) and connect the earth pin to a local rod," then this sounds like "TT-ing your shed" without a sub-board. The protective device (and additional protection) would be on one earthing system, and the socket-outlet on another. I don't know if this is relevant or not, and I've reached the limit of my knowledge about whether this would be permitted or advisable.

I suppose the way of complying to keep everyone (incluing your CPS advisors) happy would be to treat this 32A socket as a separate board and TT it. So install an RCD garage subboard with the socket nearby, put this sub-board on the earth rod, and follow the usual procedure for making sure exposed conductive parts from the two different earthing systems are not simultaneously accessible (411.3.1.1).

 

[South Spark]

Utilise the Pme for the socket,add a rod

Don't employ any Horses,Donkeys or Cows to operate the sound system and every ones happy

Where are you talking about adding a rod? To the socket (disconnect PME earth) or to the MET?

 

[davesparks]

If it is to be used for outdoor events then you'd do well to read up on the requirements of BS7909 'code of practice for temporary electrical systems for entertainment and related purposes'
This is becoming more commonly recognised in the industry, and councils are increasingly requiring compliance as part of event licensing.

As it stands you may find you have a grumpy customer on the phone when the event electrician comes along and refuses to use the socket as it is non-compliant.