seperate bonding conductor

[ianphilip007]

hi

when running a 10mm bonding( seperate to the cpc proctected distribution circuit) conductor for a pme supply to a detached garage that contains (water/gas services) is it ok to run from exisitng house cu to gargae cu and then bond the services to garage cu. or does the bonding conductor have to be unbroken all the way back to the house cu

many thnaks

 

[Engineer54]

When you think about it, Hot Tubs and jacuzzis would be standing on a wooden decking, or a concrete base with a wooden decking surround and with steps. You would be mad to locate one of these units on bare ground, i've certainly never seen one. All these units have the tub's made from a glass fibre, any earthing on the unit is limited the pump and heating plant, even the pipework is all PVC, even if permanently piped in.

The chances of taking a belt in such circumstances, is pretty remote, about as remote as kids playing with a hose pipe or plastic paddling pool on hot steamy days in the back garden!! Though i can't see why you shouldn't take the extra precaution of staking the the tub installation....

 

[La Poste]

Though i can't see why you shouldn't take the extra precaution of staking the the tub installation....

Could you explain why it would be safer to stake the tub as well as have PME?

Is it something to do with bringing the touch voltage down in the event of a lost neutral?

Thanks.

 

[Engineer54]

Your just keeping the potential equal to the surrounding ground potential. Personally i would only consider using a rod where the supply is PME/TNC-S. Isolating the supply PME earth before connection to the Tub's plant supply, and replacing with the electrode's earth. You will obviously need to make sure there is suitable RCD protection, but that is normally covered in the tub's electrical system, by the manufacture. I've haven't seen one that hasn't been integrally RCD protected for years now!!

I can't honestly say i've ever rodded a Hot Tub or Jacuzzi professionally. Never rodded any i've done privately for friends etc either, of which there have been plenty in Cyprus. But then there is no domestic PME/TNC-S in Cyprus... lol!!

 

[La Poste]

Ah right I thought you meant rodding at the jacuzzi as well as being connected to the PME supply.
You know having both at the same time.

The subject of earth rods is really interesting you said that in the fifties all council houses had rods fitted as well as being connected to a TN-S earthing system.

What would be the point of rodding if you were already connected to a cable with an EFLI of 0.8 Ohms or lower?

I've also heard it said that it is good to rod at the consumers installation if they have PME so that PME and a rod are both used together at the same time, I am just trying to figure out why.

Why would you want an earth rod and PME both fitted together in the same earthing system?

Thanks.

 

[Engineer54]

Fitting an earth rod at origin of the installations supply on a PME supply is like adding another rod to the Multiple Earths of the PME supply, better to know that the first rod is close to your installation rather than up the road a piece!! lol!! Just make it a good rod though, a standard UK 200 ohm rod will be next to useless!!!

As for the the old council habit of installing a small earth plate or rod to TN-S supplied houses etc, no idea the thinking behind it, but can't see any down side to it either...lol!!!