Meter Form Identification

Electric meters have a faceplate that gives you the information you need to correctly exchange the meter. The face plate will tell you the serial number and/or a unique identifier, these are utility specific. You will locate the form sometimes listed as FM. Meter form is a universal classification of meter style. You will also find the class of the meter. When exchanging a meter, we always change LIKE FOR LIKE! The form and class must match the old one. Failure to replace a meter with the exact same meter can result in many issues up to and including fire, explosion, injury and even death.

1. The first information you need to verify is the serial number or unique identifier. The serial number/unique identifier verifies you are at the correct location and the correct meter. Going by the numbers of the house/building is not enough. Some houses/buildings have multiple meters for that location, e.g. some houses have meters on the house and a separate meter on their garage. Even if the serial number/ unique identifier is one number or character off do not assume it is a data error, you are more than likely at the wrong meter. As you will learn meters come in boxes of 4, typically the serial number/ unique identifiers are in numeric order. If you are looking for meter 12345678 and find 12345679 the correct meter could be nearby. If you truly believe there is a data issue report it to your Field Manager so they can dig deeper.

2. The second verification is the Form (FM). This will say 1s, 2s, 3s, 4s, 5s, 7s, 8s, 9s, 12s, 14s,15s,16s, 20s and 30s. Each meter form is unique for its application. At first you will only deal with 1s, 2s and 12s. It is imperative you replace like for like. Placing a 1s meter in a 2s socket will result in an explosion which can result in personal injury and/or property damage. The meter will be damaged beyond use.

3. The third verification is the Class of meter. The Class is reflected by the Test Amperage. If you place a class 200 in a class 320 socket it might hold but once increased use of amperage happens such as an elevator the meter will blow up causing property damage and possible fire.

4. Wire Count, for example, 3W = 3 wires (2 hots & a neutral), 4W = 4 wires (3 hots and a neutral).

Meter voltage rating

• Meters have voltage rating on the faceplate. If the old meter says “voltage 240” and the new meter says “120” you cannot use the 120 volt rated meter to swap the old meter.

• If you do not have the correct meter do not replace the meter. Call your Field Manager to get the correct meter.

Pass through meters vs CT meters

There are 2 basic types of electric meters, pass through (self contained) and CT meters.

• With a pass through electric meter the electricity goes into the top of the meter (line side) and comes out the bottom (load side) by removing the meter you are able to disrupt power (shut off power) 1s, 2s, 12s, 14s, 15s and 16s are pass through meters. When you remove the meter, you interrupt power to the structure.

• CT (current transformer) meters are used typically in commercial settings where the wattage and amperage is much higher than where a normal pass through meter would be used. The CT's are large copper coils placed around the service feed. The coils pick up the electromagnetic field from the wires. The more power used the stronger the electromagnetic field. CT meters have a lower class level typically class 20. The meters are energized but do not carry the load through the meter like the pass through meters do. Examples of CT would be - Class 20, 100 vs 200 vs 320.

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