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Controlling your risk by Bob Carruth

As Risk Control Manager for the NCACC, Bob Carruth manages the operation of the Risk Control Team for the Risk Management Pools. The team assists members with development of safety policies and programs and identification of liability exposures and controls. Carruth is a Certified Safety Professional and is certified as an Associate – Risk Management.  For archives of this column click here

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Oct 26

The Hidden Dangers of Space Heaters

Posted on October 26, 2015 at 1:05 PM by Todd McGee

With the arrival of the cooler fall air, our attention turns to football, BBQ, colorful leaves and how we plan to keep our feet warm at work. We want to make our personal nests at work as comfortable as possible, so we bring items from home to make it so. These include many of the personal, electrical appliances we use on a daily basis. In fact, in a couple of instances I have been in some offices that looked like a dorm room, but that is another story for another time!

What are defined as “Personal Electrical Appliances”? These include coffee pots, microwaves, refrigerators, potpourri pots, lamps, fans, and space heaters. These are “comfort” items and help make an office more comfortable for the user. Although it might seem that there is no harm in allowing these items to be brought into the workplace, their addition can create a very dangerous situation that could result in extensive property damage, catastrophic injuries, or even death from fires or electrical surges.

Although each one of the appliances mention above are problematic in the workplace, coffee pots, microwaves and space heaters pose a greater hazard due to high wattage that each one of them needs to operate. Of these three, the space heater is especially hazardous. As I write this, the NC PRIMA listserv is lit up (no pun intended) with discussion about the various policies organizations have in place regarding space heater use.

Managers and supervisors are faced with the same dilemma every fall – whether or not to allow space heaters to be used in their facilities. Since many of our public facilities are older, with aging HVAC systems, or have internal configurations that have changed since the original construction, there are spots in every building where the heat just won’t reach, or that may have more drafts from the outside. Employees often push back against policies that ban the heaters, because they are seen as safer than ever, and the answer “because that’s the policy”, or “that’s a directive from the fire marshal (or insurance company)" doesn’t answer the question “Why?”

Let’s look at why space heaters are such an issue. In an electrical grid, the electricity is always flowing. It is also seeking the fastest way to get where it wants to go, and that is into the ground. It will also seek the path of least resistance. Along this path, we steer and restrict its flow. The wiring in our buildings is not as big or capable of carrying the large amount of electricity that exists on the outside utility poles, so there are transformers installed in the system to reduce the amount of power coming into the building. Circuit breakers are placed at critical places to interrupt the flow of electricity if the level gets too high. Too much current flowing through a line can cause the electricity in it to overheat the system and eventually lead to the electricity “escaping” from the wire it is contained in and destroying anything in its path to get to where it wants to go – the ground.

When a space heater, or any other high demand appliance, is plugged into a wall outlet, the electricity senses what is needed for that appliance and the available power begins to rush to that appliance. When the capacity of the wiring and associated circuit breaker is exceeded, the breaker will trip and the power is shut off – if the breaker is working properly. If this didn’t happen, the circuit would continue to overheat, weakening the wiring and its ability to safely handle the electricity flowing through it.

The typical wall outlet is wired to handle about 2400 watts of power and there are usually multiple outlets on one circuit breaker. Since space heaters require about 1500 watts of power to operate (as do coffee pots, toasters and most microwaves), trying to operate more than one on a single circuit will overload the circuit. The problem arises not in the single space heater being plugged in but when multiple ones try to share the same circuit or someone tries to use a space heater while running a microwave or other large demand appliance on the same circuit. Power strips don’t help, as they only exacerbate the issue.

One of the major causes of structure fires in the U.S. every year is overloaded wiring. As a wire becomes overheated, the insulation covering the wire gets soft, and since the electricity is always trying to find an easy path to ground, a weakened wire in close contact to a metal surface close by can literally “explode” and ignite anything that is combustible between itself and the service it is trying to reach. What makes these fires even worse is they often begin in hidden areas and may smolder for hours before being detected. This means that when the fire is finally noticed it may be too large to easily control.

Finally, there are two other reasons for discouraging the use of space heaters. If there is a problem with the heat in a building, it is only made worse with the introduction of space heaters, as it confuses the thermostats and other sensors by heating the air in spots in the building, thereby confusing the main heating system. Also, many of our computing systems are sensitive to power fluctuations that may be brought on by the increased load demand on the building’s electric system. This can lead to costly repairs or other issues on our computing systems.

So, in summary, here are some take-aways:

Continuous tripping of one or more circuit breakers is a symptom, not a problem. An investigation should be performed to find out why the breaker is tripping to correct the source issue.

Careful consideration should be given to the age of the building and the condition of its electrical system before space heaters or other personal electrical appliances can be used. The older the wiring, the less tolerant it is of overloads.

Extension cords & power strips should never be used with a space heater. Extension cords are often not rated at the same level as the building wiring and can become overheated quicker and subject to catastrophic failure before the circuit breaker can trip.

If space heaters are allowed:

They should be for temporary heat only, primarily to provide supplemental heat.

All space heaters should be equipped with a safety shutoff when the unit is tipped over, and the cord should have a functional ground prong.

Careful consideration should be given to what outlets are used for space heaters, to insure multiple appliances are not plugged into the same circuit.

Periodic inspections of all heaters should occur, to check the wiring, functionality, etc.

Never use the same circuit for a space heater and electronic equipment such as printers, copiers, or computers.

Hopefully, this will help your employees better understand the dangers associated with the use of space heaters in the workplace. If you need further assistance, or have additional questions, please feel free to contact a member of our risk control staff.