ECN Forum Forums Photo Discussion Forums Photos for General Discussion Light Pole Violations

HotLine, it’s fairly common to provide overcurrent protection for street lighting in the form of a submersible fuseholder with a UL class-CC fuse. They can be hidden in subsurface concrete boxes or in pole bases at the handhole. In more recent underground-fed poles, typically municipalities specify an equipment-ground conductor routed with the circuit conductors. A ground rod or a ‘Ufer-like’ flat coil of ~6AWG solid copper at the concrete-form base is often called out, but as supplemental ground electrode for lightning protection. Think about it—metal light standards make superb “air terminals” (lightning rods.) An example of a submersible fuseholder is the Bussmann HEB-series part. http://www.bussmann.com/library/bifs/2127.PDF Littlefuse and Shawmut sell ‘em too.

For overhead duplex spans to metal poles, it’s possible to treat the situation as it if was a junior unmetered 2-wire service entrance, and bond the grounded-circuit conductor to the electrode and pole metal. Agreed that there may be older installations where a street-full of metal poles is served by a pair of unfused overhead ungrounded conductors, where a ground fault in a pole would not clear an overcurrent device. An old school of thought may have been that no overcurrent protection meant fewer outages, but discharge-lighting ballasts can blaze nicely if there’s no upstream overcurrent protection.

Properly sized streetlighting fuses have another feature—if a ballast craps out and its local fuse opens, the rest of the circuit still runs.

This ground rod or not to ground rod topic has been driving me nuts for the past month or so. I've been trying to get all the information I can on the subject. I need to install 10 light poles, ur, um, Standards. I have come to the concusion that the ground rods are not installed for short circuit ground fault protection but for lightning protection when installed with surge protection. The short circuit ground fault protection is supplied by the EGC ran with the circuit condutors. There should be no bond or connection beween the two other that what is made through the fixture, ur, um Luminare. Does it sound like I'm on the right track? If so, where do you put surge protection on a parking light circuit?

Blessings, Mark

Bjarney,
I'd agree with you on the fusing of street-lights, over here we use HRC fusing in each standard.
Hotline,
Using GFI protection on Line equipment would, to a certain extent, be a waste of time and money, in that, Insulators, by their virtue, attract dust during dry spells, when the air moisture level increases, this dust becomes damp and you have an instant tracking problem, that can cause a small leakage current to Earth, via cross-arms(wooden or metallic).
Even at Low Voltage, this can be a real problem.