Very low reading of PFC test

[trev]

what did you use for a rod. a scaffold pole?

Now that opens something up for discussion (I've seen scaff poles used Tel, don't ask)
Imagine a tube of copper about the same diameter as a scaff tube, would it have a beneficial affect of the Ra because of the increased surface area and because of 2 surfaces in contact with earth.
I'd say yes but the problem would be the malleability of the copper itself.

 

[HappyHippyDad]

Now that opens something up for discussion (I've seen scaff poles used Tel, don't ask)
Imagine a tube of copper about the same diameter as a scaff tube, would it have a beneficial affect of the Ra because of the increased surface area and because of 2 surfaces in contact with earth.
I'd say yes but the problem would be the malleability of the copper itself.

Now thats interesting! You've increased the surface area but decreased the actual volume of copper.. I'll have to think!

 

[trev]

I've just read that again and realised it's pretty poorly worded.
Obviously the increased diameter would have an effect. A 5/8 rod is always better than a twig but would the fact it's a tube be beneficial

 

[HappyHippyDad]

I've just read that again and realised it's pretty poorly worded.
Obviously the increased diameter would have an effect. A 5/8 rod is always better than a twig but would the fact it's a tube be beneficial

Thats what I thought you meant. The resistance of a tube would be greater though wouldn't it compared to a solid rod with the same CSA?

 

[Silly Sausage]

Would a holey tube be even better?

I'm fooked if I know!

 

[trev]

Thats what I thought you meant. The resistance of a tube would be greater though wouldn't it compared to a solid rod with the same CSA?

Probably mate, I've had a **** day and I'm more than likely talking it. Ignore me, I'll put it down to hallucinations

 

[HappyHippyDad]

So its comparing the greater resistivity of the tube to the greater surface area in contact with the earth! We need an equation!

 

[Silly Sausage]

So its comparing the greater resistivity of the tube to the greater surface area in contact with the earth! We need an equation!

I know of the very document that covers all this, but I can't be bothered to find it right now.
Maybe later...

 

[trev]

So its comparing the greater resistivity of the tube to the greater surface area in contact with the earth! We need an equation!

No we don't. I need a beer.

 

[Guest77]

you wouldn't get 0.22 where Hippy lives, it is all cotswold stone in the ground, I had 3 rods screwed together at Minchinhampton and still couldn't get under 100 ohms lol, to get 0.22 the ground would have to be pretty special.

 

[HappyHippyDad]

I know of the very document that covers all this, but I can't be bothered to find it right now.
Maybe later...

No we don't. I need a beer.

Great!! I get all excited about an interesting electrical point and you two go and drink beer!

I might actually test it myself. Copper tubing readily available vs 5/8 rod!

...................

No i wont.... thats just silly!

 

[davesparks]

I don't think a tube of the same diameter will show any real increase in Ra.

 

[telectrix]

but what if you fill the tube with green kryptonite? SUPERROD.

 

[driverman]

hi,
I did Ze test, I got 0.22 ohms but PFC test I got 22 Amps. it is very low. I am expecting a (230/0.22=1045 amp ) by theory
So pls let me why it is very low reading

You may of got the Ze reading wrong in first place and the PFC was correct. Having said that you can get low Ze readings.