correct way to test potential difference?

paulthemagpie · Jan 25, 2015

elo guys,

could someone explain how to test the potential difference between the main earthing and water pipes and what test instrument i should use?

paulthemagpie · Jan 25, 2015

i always thought it was using a voltage detector across the 2 points, but then when i thought about testing the voltage on a 3 phase system when placing the 2 prongs across for example L1 and L2 it gives a reading of 400v. Shouldnt they be no potential difference if both had 230v through them.

can anyone help me understand this as it got me confused.

Guest77 · Jan 25, 2015

A few tips for you

(1) ac waveline
(2) degree difference between phases
(3) star connection with neutral not connected
(4) the figure 1.732
(5) ohms law

let me know when you have had a think about it.

Leesparkykent · Jan 25, 2015

[PDF]Guidance on Protective Conductors - Electrical Contractors ...
www.eca.co.uk/filelibrary/download/?FileID=1284
the main earthing terminal of an installation”. ... parts at substantially the same potential”. ... An acceptable test to establish whether or not an item ... measure the insulation resistance between ... 1) Incoming plastic gas and water services pipes.

Guest77 · Jan 25, 2015

paulthemagpie said:
elo guys,

could someone explain how to test the potential difference between the main earthing and water pipes and what test instrument i should use?

Try ringing your local college to obtain access to a course there.