Voltage Leakage on ATS Panel

Since the neutral is normally tied to ground at the mains panel, the 19 Volts represents a resistance buildup on; your neutral or return line, or a bad ground on the equipment it is feeding.

This is a safety issue. Basically your equipment now is floating at 19 volts. If someone touches the equipment and ground they could get a shock.

The proper thing to do is the next possible down time, disconnect and clean the contacts on the neutral lines,(both ends of the cable) and the grounds on the equipment. You want to get the resistance to ground down below 1 ohm. At worst you may have to replace some ground cables.

In my experience, it is usually the grounds that are the problem.

If the technician used the proper calculated size of ground cable (same size as what is already on the equipment) it should not be a problem. Otherwise it is a temporary solution until your cabling is repaired.

I do not know the code requirements for your area, and can only relate my experience with the NEC (National Electrical Code, USA). First, all your sources should have the neutral (grounded conductor) bonded the the ground (Grounding conductor) at the source. The intent is to allow the grounding conductor to carry any fault currents back to the source and allow the over-current devices to operate and open the fault. Based on what you described, this will likely eliminate the voltage you are seeing between your neutral and ground.

If after doing this you still have a voltage between your neutral and ground, there are a couple of approaches you can take to find the problem. Does the voltage increase as you take measurements further away from your source? This could indicate voltage drop on the neutral itself. You can also take voltage measurements across the connections in the neutral system to identify bad connections. Another possible problem may be bad connections in other parts of the grounding system; an open grounding system will have imposed measurable voltages.

(1) The residual voltage can cause problems with your equipment especially if you have any solid state devices for example if you have LEDs in the system they may be dimly lit when they are supposed to be off. In one case I encountered a solid state relay that would not shut off due to the small amount of current that was being produced due to resistance in the wiring. This will probably not do serious damage to the devices, but it could reduce the life of them. As Techno stated, the most serious hazard is the risk of electric shock to people around the equipment.

(2) Lendog was correct in stating that the 19V you are measuring between neutral and ground is due to resistance in the wire. If the problem is on the load side then the proper way to eliminate it is to bond the neutral to the equipment ground usually at an electrical distribution panel (such as a breaker panel or fuse box) that is powered by the generator. Generally a bonding jumper made from wire that is close to the same size as the neutral conductor is preferred, but it is very common to use a jumper that is one or two sizes smaller than the neutral. If the generator itself is shocking you then your technician was correct to install a bonding jumper on the supply side of the generator as well.

(3) Bonding the equipment this way will actually help protect it from lighting if you install a grounding electrode that is tied to your equipment ground. In the US we usually bury two rods made of copper and steel in the ground near the distribution panel this helps direct a lightning strike into the earth.

A voltage difference between <...Earth...> and <...Neutral...> is normal when the supply is loaded. It simply expresses the current flowing in the <...Neutral...> conductor, its material, diameter and its length; no conductor, apart from superconductor materials, exhibit exactly 0 Ohms.

However, <...about 19V...> is on the high side, and suggests a poor <...Neutral...> connection, a poor <...Earth...> connection, or both, or an undersized <...Neutral...> conductor. And if the <...Neutral...> conductor is undersized then the line conductor might be similar. So it's worthy of investigation.

So, get the installation tested at the earliest opportunity by a qualified local Electrician, who may be able to identify and correct the issue.

Doing otherwise risks life and limb, and also foreshadows a measure of unpopularity with the company providing fire insurance cover for the facility.