DYN 11 Tx. Neutral and Ground

Irrespective of any N-G voltage, either the computers should be double-insulated (so there is no possibility of any mains voltage coming into contact with any exposed metalwork), or all exposed metalwork should be grounded.

If people using the computers are getting shocks when touching them, either it's static (that they've accumulated while walking over carpets etc.) or there's something seriously wrong with your wiring.

Find a qualified electrician, and get it checked.

poor grounding, or neutral not bonded to ground on the secondary of the transformer. last possibility is instability between the step up and step down transformers, possibly because they lack good grounds or a common ground between them.

Is it true that this type of a transformer i.e DYN 11 Type SKTC9 does not have its neutral bonded to the ground on the secondary side? please note that the secondary voltages are as follows:- Live-Neutral=240V

Live-Ground=127V

Neutral-Ground=113V.

GA

First good answer reading down from the top.....the situation could be dangerous as it is at this time, it looks as though the original installer did not do a good job.....he should use another company.....

113 volts from neutral to ground?? Say what?? Starting to sound like you have an early retirement plan for some of your workers....

Lets try a simple test. Hook a small 110volt light bulb from the chassis of one of the computers to some external ground. A water pipe will do. Does it light up? Even a little? If so, there's probably enough voltage/current to kill someone.

If that is the case, then you really need to do something about this quick. Find a competent Electrician/Engineer or whatever you call them in your neck of the woods and get this problem taken care of.

So far, I do not see enough info to offer any guesses as to what is wrong, or has gone wrong with your system - But get it FIXED!!

I observed the electric shock on body of some equipment when phase and neutral connections are reversed. That is , in a socket out let if connect phase and neutral reverse and plug an iron box , there is a chance to get electric shock from iron box. In this case it is not related to the transformer.

I will request you to check the voltage between phase and earth as well, if it is approximately 110 -120 volt, it indicates that neutral is floating with respect to phase.

In such cases you have earth the neutral of the isolation transformer if installed in between or the neutral coming out from the UPS is to be grounded.

This is based on the similar problem faced by me in the past.

Subhash

hmmm... i completely understood the problem you are facing.

Firstly... there is failure in the grounding system. This means that the ground wire is floating and not been connected to any earth pit.

Secondly... As u said that the electric shocks are found in the computers. Please check whether the power to computers is fed from electronic spike busters. Many times Electronic spike busters malfunction.

What you have to do is;

1) Keep the tester on the ground line continously (which will glow for 100V also) and remove the plugs of spike busters or any other equipments having ground pin.

2) During this checking whenever the glowing tester goes OFF, check which plug was removed.

3) Rectify that particular spike buster or equipment.

hope this will help u in tracing the problem.

so, to sum up, probably either

1. neutral not bonded to ground

2. floating ground, as Yooogs said

3. bad spike buster [or UPS powering computers]