Landing a ground wire on a neutral terminal

[croberds@ase]

First post to the forum here.
I am running into an issue with a phase loss monitor. The monitor is for a 480vac 3 phase system. It requires A,B,C phase + neutral. The systems we install never require a neutral to be added. Our customer keeps requesting that we just put a ground wire on the neutral terminal so the phase monitor has a reference point.

My question:
Can I land a ground on a neutral terminal that isn't identified with the G/N symbol? Would this count as "bonding" the ground and the neutral? Any code references would be greatly appreciated. Thanks all!

 

[meternerd]

You didn't say if it's 480 grounded Wye with no neutral or 480 Delta. Most phase monitors are really only useful on grounded 480 Wye systems. They tend to burn up on ungrounded 480 Delta when a primary single phase situation occurs and an "open Delta" where one secondary leg is missing will usually not trip the monitor. If it's a grounded 480 Wye system, connecting the neutral of the monitor to ground should be fine. The internal impedance of the monitor will only allow a very small current to flow back to neutral. Be aware, though, that a blown primary fuse on a 480 grounded Wye underground service may not cause a phase monitor to trip. Most pad-mount utility 3 phase transformers are "common core" types, which will keep all 3 phases hot if a primary fuse blows, but with slightly unbalanced voltages. At least that's my experience with our pump stations.