weaker electrical systems to lightning faults

[old67cajun]

working an inspection where equipment fault is higher than expected from lightning. given the opportunity to propose a rewire my first question is which type of circuit has less risk to operate. field equipment is currently feed by a balanced 203 voltage phase to phase from the secondary of wye transformer. my thought is a phase to neutral 120 volts may have less faults from lightning or other transients.

 

[ptonsparky]

Is the equipment rated 208?

 

[paulengr]

Lightning doesn’t care. It just seeks a connection to Earth. System voltages don’t matter. Shielding (lightning rods) and BIL is what’s important and those have nothing to do directly with system voltage. Unless you are designing transmission lines.

Google the term “insulation coordination”.

 

[ptonsparky]

I’m wondering what balanced ‘203‘ means in this context or if it actually matters. (Assuming a typo).

Is the center point bonded and grounded properly?

How do you know it’s lightning? Yes, flash, boom, smoke is a good clue.

 

[paulengr]

What I usually find is I do a grounding inspection and find grounding and bonding issues. Since the grounding is faulty lightning then takes the alternate path through the normally insulated power conductors and rips through equipment particularly motors and sensors which have relatively thin insulation. Once you find and fix grounding, the issue is normally solved. This by the way is looking at structural grounds, not the electrical system per se. Then just look closely at incoming power. They say lightning can travel for miles in air horizontally. Imagine what it can do on a poorly grounded power line. The answer by the way is not just.a “whole house surge arrester” mounted at the main panel. That protects that one spot. Surge arresters need to be spread out and the closer to critical loads the better.

Most of the time equipment is well protected by properly grounded structure. If this is not present adding “lightning rods” or shield wires is the only practical choice but often it can be disguised so it doesn’t look like a 19th century antique.

 

[tom baker]

Re: Surge protection
More is better. You get what you pay for (Mike Holt)

 

[old67cajun]

apologies for the non responses. subject concerns tacker systems for utility size pv power generation. design showed connection of a (ac 2 dc) converter tied to 120v ac source attaching input line to source line through a fuse then input neutral to source neutral again through another fuse. actual field wiring found input line connected to a leg of 203 wye and input neutral connected to another leg of 203v wye. system blows fuses frequently during lightning storms. I thought that this wiring supply to converter could be increasing the likely hood of fuse faults of using two ungrounded conductors to supply the converter.