Horn Bypass

[czars]

On a residental meter enclosure, what is a "horn bypass". I see it called out in the Square D catalog for some enclosures, but I have no idea what it is or what it does.

 

[benaround]

Czar,

Just did a search, horn bypass is like a lever bypass for ringless res. meters.

 

[jim dungar]

There are several methods available to allow a meter person to by-pass the meter. Bypassing a meter prevents an arc from being drawn during device replacement. Each utility has there own requirements.

Automatic ones operate on a plunger and work as the meter is removed. (these are rare)
Slider types have a ring located under the meter that must be pulled or pushed. (usually on small services with low fault currents)
Lever types have an operating lever along side of the meter (these are common at 320A)

Horn style have "horns" next to the wire lugs that provide a connection point for jumper wires (very common on 200A services)

 

[Big D 40]

I used to work as a lineman for the power company. The Horn Bypass was used to keep the load applied while pulling a meter. It is most often seen in 3 phase applications so that there is no interuption of service to a business should a meter need to be pulled. In residential applications it is usually on older meter sockets and quite frankly I don't know what purpose it would serve except to give someone free electric. Be very careful with these types of applications because it is easy to have the bypass stick when pulling out the meter and could cause a flash. Been there done that!