ground system has 24 v +or-

The answer is quite simple and obvious. The 'anythings' are not properly safety grounded. If properly bonded, there voltage differences would not exist to cause shocks.

In the meantime, why would those units become hot. One reason might be units are being switched off on the neutral wire and not on the hot wire.

Even with an isolation transformer, there should be one part or side of that isolation transformer bonded to ground.

Obviously something is electrically hot due to a failure. If not the HVAC unit, then something - anything - connected to that unit via wire or pipe.

In an interesting similar situation, one house was not properly earthed. A failed neutral inside that house caused neighbors homes to become hot on wires not normally so. For example, other neighbor phones rang constantly until the electric company located which house had the failed neutral. Gas pipes and CATV wire were some of the conductors carrying the 'hot' juice into other homes.

Best to start with the earthing requirements for each and every incoming wire and pipe. Because of so many failures like this, many jurisdictions now require gas pipe to be bonded (safety grounded) with everything else in the building.

There is no reas> i have a situation where the homeowner is getting shocked when he

Sounds like the safety ground is open at the panel. Not sure about the AC or the transformers have to do with it. Could be a nuetral problem as well.

Your talking separate structures right? Sounds like there are issues in the other homes to allow this to happen.

if the homeowner is touching something (like the chassis of a dishwasher) and getting a shock he must be touching else at the same time that is at a different potential. either that it the energized device has RF on it.

call in a licensed master electrician. this is no time for fool around with freebee advice on the internet. get it fixed before someone gets hurt. if you already did that call another one.

Hello, and I frequently see grounding topics posted here that seem to suggest that you WILL have a safety (electrical shock) problem if a device is ungrounded. If there exists an unsafe potential difference between some metallic location on or in the device and a grounding system to which that location is to be tied then you have a fault condition. It is the fault that should be located and repaired FIRST. A grounding system is intended to carry significant current only under a fault condition. Using grounding as a bandaid to cover up a fault (assuming you don't blow a fuse or trip a breaker) is unwise. Sincerely,

John Wood (Code 5550) e-mail: snipped-for-privacy@itd.nrl.navy.mil Naval Research Laboratory

You nailed it. That "scratching their heads" had *nothing* to do with the electrical problem; it was an indication that they didn't understand why anyone would expect *them* to spend their time and money to fix it, rather than call a qualified electrician.