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Standards Division

LP Gas Concerns > Electric Meters

Richard Fredenburg, LP-Gas Engineer

Electric Meters - A Source of Ignition?

In light of recent calls to us and to the North Carolina Propane Gas Association office and because of the dwindling "real estate" available for placing a small container beside a building, we looked again at our policy on whether or not electric meters are sources of ignition. The quick answer is that they are not, but there are some qualifiers now. Please read the entire article and do not take the above statement out of context.

The first qualification is that very few, if any, electric power meters at residences and businesses are "explosion proof." They do not carry a Class I, Division 1 or 2 classification. As such, they are not guaranteed to not generate sparks. However, the nature of their construction is that there are few or no spark-producing contacts in the housing. The housing protects the meter from weather and typical things people do around the house. A good weather seal acts a lot like an explosion proof seal. Based on this information, we do not consider the electric meter within the weather seal housing to be a source of ignition.

However, the electric meter housing is attached to the house by means of a receptacle in the meter base. As with any electric receptacle, if something plugged into it comes out, there is a good chance that a spark will be generated. When the meter is properly installed on this base, a seal is applied that helps prevent the meter from falling out. When the seal is intact, the possibility that the meter will come out of the receptacle is extremely low.

Sometimes there is a power interrupter system attached to the electric meter that allows the power company to remotely interrupt power to a water heater, air conditioner, or heat pump. We do not know how this device operates or how effective the seal is. Looking at the one on my house, the seal where the wire goes into the housing is not tight. If the electric meter at a house has a power interrupter device nearby, that power interrupter device is considered a source of ignition. If you can find documentation otherwise or if it has been deactivated and bears a label applied by the power company clearly stating that it has been deactivated, then it is not a source of ignition.

Usually there is a fuse or circuit breaker box near an electric meter. Again, if the fuse blows, if the circuit breaker trips, or if someone does something to open the circuit at this box, there is a real possibility that a spark will be generated. Usually this box sits there waiting for the rare times that some electrical work is going to be done that requires all power to the house be disconnected. Unless someone is getting ready to work on the electrical system of the house, the possibility that a spark will be generated in the breaker box is extremely low.

We also feel that the possibility of a relief valve discharging when a spark is generated from either of these devices is extremely low.

And that leaves the question about placing a propane container near the electric meter or the breaker box. Based on the above rationale, we do not consider an electric meter or a breaker box to be a source of ignition when they are not being worked on and when the seal on the meter is properly applied and intact. If a service person is working on the meter or box or if the seal on the meter is missing or damaged, a propane container within ten feet of either device may not be filled.

We need to point out that we feel that propane containers placed near an electric meter because of this policy are not likely to be involved in an incident where propane was ignited because of the container being close to the meter. But the possibility does exist. If a driver feels that he or she is at a significant risk because of the container placement with respect to the meter, we respect that. The propane company should, too, and work with the driver and/or customer to address that concern.

If you have any questions about this policy or if you have information that we should know of with respect to this policy, we encourage you to contact us and discuss it.

Return to LP-Gas Concerns

Last updated June 20, 2007

 

 

NCDA&CS Standards Division, Stephen Benjamin, Director
Mailing Address:1050 Mail Service Center Raleigh, NC 27699-1050
Physical Address: 2 West Edenton Street, Raleigh, NC 27601
Phone: (919) 707-3225; FAX: (919) 715-0524