Installing and maintaining lighting in commercial and industrial settings was my job for the better part of 36 years. While I worked solo for much of that time, I often worked with other team members. And sometimes, my “joy and delight” was following up on installations and repairs done by others.

Lighting Up Right: Nailing the Essentials for a Safe Install

Steve Maurer, IME
Installing and maintaining lighting in commercial and industrial settings was my job for the better part of 36 years. While I worked solo for much of that time, I often worked with other team members. And sometimes, my “joy and delight” was following up on installations and repairs done by others.

For the bulk of this article, I’m going to address certain aspects of safe lighting installations:
  • Proper Wiring and Grounding
  • Insulation and Moisture Protection
  • Overheating and Damage Prevention, and
  • Adhering to manufacturers’ instructions

But first, I want to address something right here at the top: worker safety. Not just the worker performing the installation, but all workers and personnel in and around the work area. Especially when the work done is at height.

Many times I’ve seen tools and equipment drop to the floor, almost contacting a person below. Some people call it a near miss… I call it a near hit. Either way, It’s not good.

Always be aware of your surroundings, both behind and below you.

Let’s get started with the first three subtopics for safety in lighting installations.

Proper Wiring and Grounding
When roughing in wiring circuits, planning ahead and designing the circuits is a given. Because lighting is a fairly fixed load, the is fairly simple. In most residential settings, a 14 AWG conductor is often used, normally in a sheathed cable, often called Romex™. That said, a 12-gauge wire isn’t necessarily overkill and can be useful is expansion is possible in the future.

However, in commercial and industrial applications, selecting the proper wire size is more nuanced. The lighting circuits are often larger, more complex, and will connect lamps and fixture of a higher wattage than residential installations.

Additionally, the location and environments in commercial, but particularly in industrial applications must be taken into account. We’ll talk a bit more about that when we discuss insulation. But always take into account the environment when specifying the conductors.

It’s also important that proper identification and labeling practices are used, perhaps more so in lighting than other common circuits. I say that because of the need, in most cases, for a switch leg to control the lamps or luminaires.

In residential applications where 2- conductor with ground sheathed cable is used, it can get confusing as the two conductors will be black and white. A switch leg uses both conductors as hot, so marking the neutral wire as a hot is essential.

With LED fixtures, control is often low-voltage, landed on the driver. Of course, that means you can use a smaller conductor for lighting control. And some sheathed cables are manufactured with dedicated color-coded control wiring molded into the cable.

But in any case, make sure that control wiring is identified, marked and labeled as such.

Ensure that all connections to the fixture are properly made. It can be tricky, especially when connecting stranded fixture wires to solid wires in residential circuits. If using standard wire nuts, make sure the conductors are lined up correctly and of the proper stripped length.

And do make sure the connections are tight, and waterproof if necessary. Shorts and over heating in lighting circuits, particularly those hidden in ceilings, can have disastrous consequences.

As for grounding, always follow code required practices. Remember that the ground must have an unbroken path from circuit panel to the fixture at the end of the circuit. Keep in mind that even switches are a part of the path.

Insulation and Moisture Protection
In residential circuits using sheathed cable, you pretty much got what you got, right? Although I will say that when I rewire our house, much of the wiring in the attic was underground feeding. I think they just used whatever they had on hand.

In commercial, and more specifically in industrial installations, particular attention must be paid to the conductor insulation. Follow the code for the type of insulation required. In some cases, you may need to use a hi-temp insulation, not because of the fixtures and lamps, but because of the activity and environment of the location.

Even when encased in conduit (of the proper type, of course), make sure the conductor insulation meets code requirements, particularly if there are high temperatures or the potential for contact with chemicals and moisture. Insulation thickness and composition must be factored in.

Moisture protection includes wiring practices and fixture selection. In office areas, this isn’t much of an issue. But in outdoor lighting, dusty environments and damp or wet locations, it’s a big consideration. Make sure the fixture has the correct IP rating for the area.

In boiler rooms and processing areas, water and steam are huge factors, particularly where washdown is necessary. The fixtures may need to be of an IP rating of 65 or above.

By the way, the conduit also plays a huge part in moisture control. Obviously, EMT shouldn’t be used in damp or wet locations because of moisture ingress. However, in corrosive environments, make sure you use the correct type of conduit and joining practices. Aluminum is lightweight and easy to use. But, it’s highly susceptible to damage from corrosives and may need premature replacement.

Believe me, I know from experience in processing plants. Stainless steel is more expensive to install… but its lifespan is much, much longer.

Overheating and Damage Protection
A lot of overheating can be avoided just by using proper wiring and connection practices. Loose connections are a major culprit in overheating and circuit failure. But lamps create heat, even LEDs to some degree (pun intended). So make sure any generated heat can be dissipated efficiently, particularly in high ceilings where even non lighting related activities generate heat.

Heat can also be generated by conduit overfill. Since lighting is often on for long periods of time, sometimes 24/7, the potential for heat buildup is always there. Conduit fill specifications are there for both damage protection during conductor pulling and for heat control within the conduit itself.

Speaking of damage protection and conduit, wire pulling is one activity where conductors are subjected to the most stress and potential damage. Proper pulling practices, such as using pulling lubricant and keeping to the correct bending radiuses and bend combinations, help alleviate conductor insulation damage.

Interestingly, the number of strands in stranded conductors in stranded wire can also play a factor. When I was pulling in wire for fixture in a working freezer storage area, for example, using wires with a higher strand count allowed more flexibility in the cold environment. This kept down stress on the conductors (and on me, LOL) during the pulling process.

Of course, when installing the conduit (which is itself a damage protection practice), make sure it’s properly supported and connected to junction boxes. And, hopefully, inaccessible to forklifts.

For pendant lights and fixtures, some flexibility may be required. Often this is accomplished by using flexible cord from the junction box to the fixture. If used, make sure the proper cord grips are used as well as any safety cables or chains.

Adhering to Manufacturers’ Instructions
Of course, installation following the manufacturer’s instruction is critical to maintain UL® and other ratings. The manufacturer has designed and tested the product to exacting specifications, both in design and installation instructions.

Keep in mind, though, that specs often change. I may have installed hundreds of a particular light fixture. But I always read the instructions before installing a new one, just in case there were upgrades or changes.

And… there always are.

Ignoring or not following the manufacturer’s instruction might void the warranty at the least. And at the most, could cause damage and injury to property and personnel.
Photo courtesy of Emerson Appleton
Smart Performance, Everyday Convenience - Intermatic ETW Series 365-Day Programmable Wi-Fi Timer
Upgrade Your Comfort: Introducing the Sunnata Fan Speed Control
Newsletter Signup