Tera Tera

i=p/u · Oct 16, 2013

In a TT system in commercial premises with 100mA main switch , does all circuits need to be 30mA rcd protected... Can't think of the sums for this 1. But I will say yes.

JD6400 · Oct 25, 2013

Two words ----- Mini Digger !:devil2:

i=p/u · Oct 25, 2013

Or TNT like in roadrunner

Engineer54 · Oct 25, 2013

JD6400 said:
The one's we are supplied , are steel with a copper coating and have been for as long as I can remember / have noticed !?

Edit ; I have wondered in the past if solid copper alternatives are available , but I suppose they will not really be up to the punishment , unless they are just being laid in a trench .

Yes they are available, and are only generally used for dropping into bored hole installations as they can stand very little in the way of being directly driven into the ground.... If you're going to lay an earth electrode in a trench, then far better to use copper tape rather than an earth rod. Earth rods are far too short to be of any use being laid in a trench, in the vast majority of cases.

Engineer54 · Oct 25, 2013

i=p/u said:
Well are boss said has to be less than 20 ohms. Where he got this figure I don't know.

We used sledge hammer, what else can you use? Also are them rods steel with copper coating???

Our Spec's have always called for 10 ohms or less for petrol service stations, similar to L Protection systems...

The use with and SDS type drill and rod driver adaptor or similar, is always better than sledge or club hammer to drive rods into the ground, and a damn sight quicker too!!

i=p/u · Oct 25, 2013

I mentioned that and he looked at me like I was a creator

Engineer54 · Oct 26, 2013

i=p/u said:
I mentioned that and he looked at me like I was a creator

Obviously knows little about driving rods in the ground then!! Once you have used a an SDS or similar machine, you NEVER go back to using any form of manual driving!! A job that can take several hours, can be achieved in a fraction of the time, and time is always related back to Money these days!! As a Boss he should know better!! ...lol!!

jamie-spark · Oct 27, 2013

Yes it's 20ohms it's in the blue hazardous area regs book. Can't remember the name of it. I was working in a gas plant with an ex comp spark, when I had a look at it

Engineer54 · Oct 27, 2013

jamie-spark said:
Yes it's 20ohms it's in the blue hazardous area regs book. Can't remember the name of it. I was working in a gas plant with an ex comp spark, when I had a look at it

I'm buggered if i'd ever accept 20 ohms on a Gas Plant installation!!

jamie-spark · Oct 30, 2013

Engineer54 said:
I'm buggered if i'd ever accept 20 ohms on a Gas Plant installation!!

We were happy with 1667 ohms and one of those twigs u like so much lol

Engineer54 · Oct 30, 2013

jamie-spark said:
We were happy with 1667 ohms and one of those twigs u like so much lol

Sounds about right too!!! lol!!

Knobhead · Oct 31, 2013

jamie-spark said:
Yes it's 20ohms it's in the blue hazardous area regs book. Can't remember the name of it. I was working in a gas plant with an ex comp spark, when I had a look at it

Cobblers!