Bonding issue

[TodyFx]

Old house . Failed on bonding got a read 0.26 on both water and gas. Ran 10mm earth . Cable run about 5 meters . Tested and reading still same gas pipe 0.26 water 0.27. What can cause high resistance? Multiple bonding ?

 

[littlespark]

0.26 what? if its ohms, then thats about right for a length of cable.

try the test with only the cable.... then try again after the cable is connected both ends.


If its an old house, then likely all copper pipes inside, cross bonded at every sink and bathtub.

 

[TodyFx]

Hi thanks and sorry 0.26ohms. When testing just cable getting 0.01 but as soon as I clamp it to the pipe raising to 0.26.

 

[James]

Turn the supply off and test again.
parallel paths should reduce the resistance, not increase it.

I suspect the meter is being influenced by a slight voltage difference between the two points.

 

[mainline]

Hi thanks and sorry 0.26ohms. When testing just cable getting 0.01 but as soon as I clamp it to the pipe raising to 0.26.

If the cable measures 0.01 ohms, then that's what it is you're not going to increase the resistance by adding more parallel metal, it can only go lower.

 

[Pretty Mouth]

Turn the supply off and test again.
parallel paths should reduce the resistance, not increase it.

I suspect the meter is being influenced by a slight voltage difference between the two points.

This would indicate significant current flowing through the bond wouldn't it?

 

[James]

This would indicate significant current flowing through the bond wouldn't it?

a current flowing, certainly.

significant, not sure, depends on the meters internal circuitry.
however, if their is a difference between the reading when power is off and when it is on, it suggests a fault within the installation.
if it remains the same and then it suggests a fault with the distributers earth / N

a quick check with an earth leakage clamp meter would be a good way to prove the theory.

 

[TodyFx]

Turn the supply off and test again.
parallel paths should reduce the resistance, not increase it.

I suspect the meter is being influenced by a slight voltage difference between the two points.

Yes I’ve done that as well but was still getting same reads

 

[James]

I would measure current In that earth wire.