Meter Bypass Types
When planning a meter setup for a new service, If it’s a commercial job, or above a certain amperage most utility companies will have a preference (or Requirement) on a type of bypass to be integrated with Main Service Panel.
While the bypass style can be different, they all achieve the same goal:
Allowing power to flow through the meter socket in the absence of the meter itself.
This is so the Utility Companies can work on any replacements, upgrades, or Inspections they might need to do to make sure everything is functional without causing an interruption in power to the end user.
In California (Where we’re located) there is the EUSERC Standard. Which is typical for the west coast US. To abide by EUSERC Standards, all metering must be Ring Type
(Electric Utility Service Equipment Requirements Committee)
Formed in 1983, the purpose of the organization is to promote uniform electric service requirements among the member utilities, publish existing utility service requirements for electric service equipment, and provide direction for development of future metering technology. There are approximately 80 utilities involved in EUSERC from 12 states.
***Note *** Not all EUSERC member utilities accept all metering devices that meet EUSERC specifications. So, although a device may meet EUSERC specifications, it may not be accepted for use by a specific utility company. Always check with the utility company for approval before using any metering device.
When it comes to Bypass types there are 4 main bypass styles, that fall into two categories.
Ring Type Bypass
Test Block Bypass (TB)
The Test Block Bypass allows the technician to manually install a set of bypass connectors extending from the line to load side connectors feeding to and from the meter being tested. Once the jumpers are in place, current carrying flat washers are removed from each phase and at this point the meter is bypassed, or isolated from the circuit.
TB’s are Typically used in Commercial units
Manual Bypass (MCC)
A Manual Bypass can also be referred to as a MCC. Which stands for Manual Closing Circuit.
The Manual Bypass Consists of a threaded stud and keps nut on the line side bussing and the load side bussing, on each phase that will accept a utility company supplied jumper.
MCC’s are typically used in residential units
Ringless Type Bypass
Horn Bypass
A Horn Bypass has short bus connectors extend upward from the line side and downward from the load side meter socket jaws. The ends of these bus connectors give the appearance of horns. One jumper cable per phase is manually installed by a qualified service technician creating a path for current to flow once the meter is removed from the socket.
Lever Bypass
A Lever Bypass is supplied with a swing arm or lever extending from the right side of the meter socket. Once the ringless meter socket cover is removed, this dual function lever may be manually rotated upward to engage bypass rotor blades into line and load bypass jaws allowing current to flow through the meter socket with the meter in or out of the meter socket.
The second feature this lever provides is a jaw release function. By rotating the lever up as far as possible the spring-loaded meter socket jaws are spread open for ease of meter installation or removal.
The third aspect of this lever is that it prevents the cover from being installed when the bypass is operational, stopping current flow while no meter is present.
When Selecting a Meter, always make sure to consult your local utility company as they will have the final say before approving and supplying power.
For additional information, along with resources and references for this information, refer to the following: