Installation Guide

LED Lighting Surge Protection Modules

Design and Installation Guide

Introduction

LED lighting is increasingly replacing legacy light sources (mercury vapor, metal halide

and sodium vapor) in outdoor applications as a result of technological revolutions in LED

efﬁciency (higher lumens per watt), secondary optics (better lenses/reﬂectors), and greater

thermal dissipation. However, the initial cost of installing outdoor LED lighting can be

substantial; this cost is justiﬁed and payback is established based on the lower wattage

demand, lower maintenance cost, and longer lifetime it offers. In order to protect outdoor

LED lighting from failing within an investment payback period of about ﬁve years, the lighting

must offer high durability and reliability. Transient surge events in AC power lines, which can

damage lighting ﬁxtures, represent a signiﬁcant threat to outdoor LED lighting installations.

Indirect Lightning-Induced Surge

When nearby electrical equipment is switched on or off, over-voltage transient surges can

occur in AC power lines. Nearby lightning strikes can also generate transient surges in AC

power lines (Figure 1), especially in outdoor environments.

Time

Temporary overvoltage on AC

power line resulting from

indirect lighting strike.

Voltage

Figure 1. Transient over-voltage on an AC power line resulting from an indirect lightning strike.

Lightning strikes are electrostatic discharges, which usually travel from cloud to cloud

or cloud to the ground, with magnitudes of millions of volts (Figure 2). Indirect lightning

strikes, even those that occur several miles away, can induce magnetic ﬁelds that generate

surges of thousands of volts through current-carrying copper wires, such as the overhead

and underground cables that power streetlights. These indirect strikes, which produce

levels of energy with magnitudes greater than 1000A

s, can be characterized with speciﬁc

waveforms.

Introduction and Indirect Lightning-Induced Surge