What Causes High Voltage Between Earth and Neutral?

Parrallel runs of differing potential (see ans. # 1) can be subject to 'mutual capacitance' . Cross the individual wires at all convienient points (contact is best), ie. junction boxes, terminations, etc..

When you say "between Earth and Neutral", where is "earth"? Is it a ground rod or the actual earth(dirt)?

Balance phase loads and backfeed in circuit will lower.

There have been so many CR4 blogs on this subject in the past, why don't you research those first before going through the same process all over again......?

Once you have read all of those and you still have a question, we can address that for you.....

Hi P1K2S3,

PW Slack's answer is a good starting point, the Nuetral and Ground should be bonded at the service enterance of the facility. The farther you get away from that point the greater the potential difference is in terms of resistance because of conduit capacitance of the wiring. The high voltage should not be present unless there is noise transients or spikes on the common mode (Nuetral to ground). Noise and spikes can be generated by equipment operating in the facility or by nature (like lightning strikes). Oneac makes a great line of power conditioners and ups equipment that solves this problem. Their equipment has an isolation transformer so the Nuetral can be rebonded to ground and a filtering circuit to shunt the transient current back to ground. This will eliminate the volatge differential from the electrical circuit and prolong the life of equipment prower by the power conditioner or ups.

My understanding is that the earth/neutral bonding may only be done at the substation transformer, nowhere else......double bonding being a big no no......!

Faint memory from 40 odd years ago........

See also:-

http://en.wikipedia.org/wiki/Ground_and_neutral

Hi Andy,

That is not true, anywhere there is a isolation transformer in an electrical circuit the nuetral must be rebonded to ground or the secondary side of the transformer will be floating.

Does that not in some way negate the isolation, bonding together? or do you mean the neutral and earth from that isolation transformer only....? Please explain....

I must admit I had not given any thought to isolation transformers.....

Also, where you are on this world may play a role with regards to rules & regs surely....

Because there is no direct connection between primary and secondary windings of an isolation transformer all the conductors are floating and 1 point on the secondary must be taken to ground for the Nuetral point (exception corner delta where a line is grounded). It does not matter where you are.

Even rules in this area of the neutral were changed in the USA to save copper in WW2, but were only removed from the regs book in 1996!!!

It does play a role where you are, some countries have different ideas (note I did not say better!)

There are different materials used but Copper is the premium because of it conductivity.

You don't say......

The USA saved copper by installing houses on 2 wires in WW2.......

Rules and regs are always changing and being refined. The world over.

That would not be true for TT and TN-S connections.

Earthing system - Wikipedia