Deregulation of electric utilities is sweeping the country and is now available almost everywhere. The theory is that competition in the purchase of electric power would result in cheaper electricity and make utilities more responsive to consumers. This may be good in some areas and bad in others but it does put certain new elements of an electrical system under the authority of the local jurisdiction.
Utilities have historically been exempted from requirements in the National Electrical Code. They controlled all of their system up to and including the watthour meter in a facility. Electrical inspectors inspected from the meter into the facility. That is no longer the case. It is now possible for an owner to own the electric meters and all of the wiring from the main service drop. It is attractive for landlords of large apartment projects or other multiple occupancy facilities to buy their electricity wholesale and sell it to each tenant retail. Additionally, a tenant is less likely to leave the air-conditioning or heat on unnecessarily when they are paying for its usage.
Often, there is no control or requirements on these meters. Local public utility commissions may have requirements on the accuracy of a meter but usually not on safety. What’s more is that these meters can be lethal since they are usually connected to unfused wiring. Circuit protection is usually on the load side of a meter with no protection of the meter itself. A short circuit in the meter may only be isolated by the primary protection of a transformer or a circuit protective device feeding multiple meters. When inspecting a system an electrical inspector is usually not accustomed to looking at the meter. Additionally, there may not be a clear indication as to whether it is a utility meter or a customer-owned meter. Considering that there are watthour meters on the market that cost less that $10.00 each, the potential for a very dangerous condition exists.
Wiring and devices within a facility are usually properly protected yet in order to assure safety are still required to be labeled by a nationally recognized testing laboratory (NRTL). However, a watthour meter located prior to any overcurrent protective device in the building presents a major hazard in an installation. These meters have to withstand short-circuit currents from shorts in a building and surge voltages from outside the building. In addition, sever stresses should not cause the meter elements to burn open, preventing the meter from accurately registering the power consumption. The standards to which these meters are tested take all of these possibilities into account and result in a meter that is both safe and accurate.
To be safe, watthour meters not owned by the utility should be listed and labeled by a nationally recognized testing laboratory (NRTL) just as any other electrical device in a facility. To provide further assurance of quality, accuracy and dependability, the meter should also be certified to comply with the ANSI C12 compilation of standards. These standards assure accuracy and functionality in outdoor (wet, cold, hot and humid) environments. Safety determined by UL Standard 61010-1 does not necessarily include all of the environmental conditions a meter can be subjected to. Therefore the safety testing must include many of the ANSI C12 requirements. Although, performance and accuracy are not necessarily under the jurisdiction of the authority having jurisdiction, it would be serving the public well to know that the metering is accurate, dependable in addition to safe.