Posted by AC&M

Padlock Seals are the most recognized and often used seals in tamper detection for electric utility meters. The configuration of meters varies, as do sealing procedures. One of the most common methods is to seal the meter box, or in some cases, a seal is attached to the ring that holds the meter in place. Some specialty meters might have 2 seals. The first is on the face of the meter to secure the electronic interface, and then a second seal is installed on the box or the locking ring. In nearly all cases the seal used in the United States is a plastic padlock seal.

AC&M produces 3 general types of plastic padlock seals and several variations of each type. All can be customized by color or marking to meet the individual user’s needs. The general types are:

Plastic and Wire Padlock Seals

The chosen seal for the majority of single phase and household meters is the plastic and solid wire padlock seal, AC&M model 8001. This seal became the first choice for electric meters back in the 1960s, and the utility industry continues to use this design widely. The wire hasps can be made so they must be cut to remove, or with breaking notches (scoring) to allow removal without tools.

Originally padlock type seals were made of all steel. The early all-steel version is still in use today and offers a high degree of strength and durability needed by some utilities.

Clear Plastic Jacketed Padlock Seals

More recently we find the use of advanced padlock seals with more tamper-detecting and performance features. The XPC-2 offers a clear acrylic jacket to withstand tough conditions and protect the information inside. A version of XPC with a highly readable bar-code is also available. (XPC-BC)

These jacketed seals make tampering easier to spot because it is almost impossible to force or attempt to open them without destroying the seal or leaving visible evidence of cracking on the clear cover. This system is becoming popular for use on meters that are read with remote readers or on centralized (AMI) systems. Because the meter is seen less often by utility personnel, a more advanced seal with more protection from wear helps keeps the seals in use to deter tampering, and to remain readable, for the longer periods between inspections.

Padlock Seals Made With All-Plastic

For other meter applications, seals of all-plastic are used on devices with a smaller opening, or when a seal has to break away easily.

The all-plastic seal most used in electric metering is our model 7001 Fast Seal. Sometimes called a “demand” seal due to their common use on demand meters, the Fast Seal is still in use at many utilities. Typically demand meters require a new seal monthly or at some frequent interval.

A meter technician often has only one free hand to perform a seal change, so Fast Seal can be applied and easily removed with one hand. While demand meters are becoming less common, the need for a seal to apply with one hand, or to be easily pulled off by hand, still remains in some utilities.

The design of all-plastic seals can make detection of tampering easier than with some stronger seals. There is much less to inspect because of simplicity, so the user can readily spot marks, cracks, etc.

Uses Beyond Meters

Plastic padlock seals are useful in securing other utility assets such as control and switch enclosures. Junction boxes at sub-stations, storage and inventory control of equipment and supplies, remote reading boxes. They also can serve as lockout tags for switching, junctions, and transmission connections. Other uses include line trucks, tool boxes, transformer tagging, and many more areas where movement or opening and closing needs to be controlled.

These various padlock seals used in many other industries and government sectors like medical, banking, food and air transport. Likewise, utilities use many other types of seals for specialty applications. These you can find in other parts of the web site and blog. And will be discussed in future stories.

We are proud to be suppliers to utilities of all sizes worldwide, for over a century. And equally, we take pride in our 110 year history as a leader in manufacturing all types of seals at our US owned and operated factory and warehouse facilities. Reliability, fast service, and high quality remain the hallmarks that have helped utilities trust AC&M to meet their needs for tamper evident seals.

If you have questions about our seals, or want information about using seals in your utility operations, we are at your service. An experienced seal applications expert is available any time during business hours.

Contact a seal specialist at our main office and factory: or call 1-800-342-0333 in the US or 516-349-7010 from anywhere.

Or see our website for sales and service locations outside the US.