Pme installations in 18th edition with additional rod.

[David Rann]

It's proposed in the 18th edition that any new pme installation is to have a rod added by the electrician that has has a resistance of 30ohms or less. What are people's thoughts on this? My main concern is the amount of services that are going to get hit with everyone driving rods in.....also my lowest reading on a rod ever was 40 ohms which I thought was good.

 

[telectrix]

last year on a gypsy site, i got 30 ohms on a 1m rod (sandy soil). when i had fitted 6 rods, one at each pitch and all linked with the SWA armour and 3rd core cpc, total Ra /Ze was 5.2 ohms.

 

[David Rann]

So what's your thoughts adding a rod to pme system?

 

[Sylvia Namusisi]

It's proposed in the 18th edition that any new pme installation is to have a rod added by the electrician that has has a resistance of 30ohms or less. What are people's thoughts on this? My main concern is the amount of services that are going to get hit with everyone driving rods in.....also my lowest reading on a rod ever was 40 ohms which I thought was good.

 

[Sylvia Namusisi]

It's proposed in the 18th edition that any new pme installation is to have a rod added by the electrician that has has a resistance of 30ohms or less. What are people's thoughts on this? My main concern is the amount of services that are going to get hit with everyone driving rods in.....also my lowest reading on a rod ever was 40 ohms which I thought was good.

Why speculate on the 18th edition?
It is not yet out or is it?

 

[suffolkspark]

They need to be black and white on whatever they decide, if they think that the risk of potential danger is really that great that they are going to bring this in then they should also want it retro fitting to existing installs or what's the point at all?

surely if a neutral is lost up-steam of say 10 terraced properties, say yours is in the middle and is the only one also staked..... isn't all of the current going to want to flow towards the pme link in your service head... then down YOUR stake?

I may have missed something but that is right isn't it? that stake gonna get just a liiiiitle bit warm?

 

[David Rann]

Why speculate on the 18th edition?
It is not yet out or is it?

No but the draught is....and it's in there...not speculation....just proposed

 

[Gavin John Hyde]

Would be interesting when dealing with apartment building s with PME supplies, would there be a communal rod system... or would the rod idea be advisory with plenty of exceptions..... time will tell but try telling joe public that you need to charge extra for a rod if its decided to retro fit them when doing certain jobs..

 

[David Rann]

If they can't rely on pme then why not get rid off it and make everything TT going forward rather an adding a rod

 

[Ian1981]

It's proposed in the 18th edition that any new pme installation is to have a rod added by the electrician that has has a resistance of 30ohms or less. What are people's thoughts on this? My main concern is the amount of services that are going to get hit with everyone driving rods in.....also my lowest reading on a rod ever was 40 ohms which I thought was good.

The proposed regulation is an additional electrode to supplement the supply authorities Earth so it’s not restricted to TNCS it also would apply to TN-S.
just a proposal so far nothing is confirmed.
Were do you get a figure of 30 ohms from?

 

[David Rann]

Nic

The proposed regulation is an additional electrode to supplement the supply authorities Earth so it’s not restricted to TNCS it also would apply to TN-S.
just a proposal so far nothing is confirmed.
Were do you get a figure of 30 ohms from?

Nic eic tech talk....they said if you run the calculation you are looking at 30ohms

 

[David Rann]

I did say it's proposed and to discuss? Not this is the way it is.

 

[Ian1981]

Nic



Nic eic tech talk....they said if you run the calculation you are looking at 30ohms

Must be to do with keeping touch voltages below 50v I’ve not bothered trying to do the maths as you say it’s just proposed

 

[Octopus]

My thoughts on the 18th Edition ....................

Another batch of ill thought out changes that are not required, but will make us sparks poorer.........................

As for the rods on PME - pointless IMHO

AND to be ignored too.

 

[Risteard]

What everyone needs to remember is that the rest of the world already requires an Earth electrode on a TN-C-S system and always has.

 

[123]

Is it earth electrode for TNCS or for all TN systems that's being proposed?

 

[Risteard]

Presumably any TN system.

 

[stevethesparks]

What worries me is how are we going to quote on that?

 

[KEV 1 N]

last year on a gypsy site, i got 30 ohms on a 1m rod (sandy soil). when i had fitted 6 rods, one at each pitch and all linked with the SWA armour and 3rd core cpc, total Ra /Ze was 5.2 ohms.

Bet all the rods have been pulled out now!

 

[Deleted member 9648]

My feeling is it wont happen. There are simply too many buildings where the installation of an electrode is not practical due to location and the risk of hitting unknown services. In my area recently a 2 mtr coupled rod got 186 ohms, achieving 30 ohms would have been a mission on that bit of ground.