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How the Locking Mechanism on an Electric Meter Box Works

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Electric utility companies use a variety of locks to secure your meter. These locks prevent people from tampering with the electric meter, such as changing the meter's usage readout. No matter what type of locking system a utility company installs, most of the lock cylinders utilize what is commonly called a barrel lock.


Barrel locks use pins to turn the cylinder of the lock instead of a key. A barrel lock is also used on vending machines. The key is circular in design, with slots on the end. The key slides over the barrel cylinder of the lock and turns the pins. The lock disengages, and you can then open the electric meter.

Dust Cap

The dust cap is a ball that rests on the end of the barrel lock. The device seals the barrel lock, preventing it from getting contaminated by water or other corrosive material. Once the circular pin key is inserted, it presses down on the dust cap, allowing the key to engage the pins of the lock cylinder.


The barrel lock has a beveled or sloped head around the cylinder. The head prevents the lock from being turned by pliers, vise-grip pliers or other grasping tools. The barrel head cannot be broken off.


Many of the electric-meter box locks are located at the bottom of the panel or under the meter. Some locks, such as the Sidewinder lock sold by McGard, has two barrel locks located on opposite corners of the meter panel. This type of lock slips onto the edges of the box and cover, securing the electric meter. The same key will open both locks.


The barrel locks used on electric meters are constructed so technicians can replace the parts, instead of replacing the entire locking system. You can replace the barrel, pins, casing or dust cap if any of these parts become damaged. Any one of the parts that gets replaced does not prevent the utility technician from using the same key to open the panel.

Crimp Locks

Few utility companies still use the crimp lock that attaches the electric meter. The crimp lock has a U-shaped pin that inserts into the panel button. A cap or cover slides over the U-shaped pin and is crimped into place with a crimping tool. Any time the meter requires maintenance or repair, the crimp lock is cut off by the technician and a new lock is installed. Each month a meter reader inspects the electric meter and records the readings. If the meter reader notices the crimp lock has been tampered with, he notifies the utility company.


Mitchell Brock has been writing since 1980. His work includes media relations and copywriting technical manuals for Johnson & Johnson, HSBC, FOX and Phillip Morris. Brock graduated from the University of Southern California in 1980, earning a Bachelor of Arts in English.

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