Temperature Monitoring to Abate Hot Socket ConditionsOctober 7 2013

1 The electrical resistance between the socket jaws and the meter blades can increase to the point where there will be an arc or significant heat buildup between the blade and the jaw in which heat is generated in accordance with Ohms law which states

power = heat = current squared x contact resistance or W= I2 x R.

How Meter Sockets Can Generate Heat

2Electric meter socket jaws not properly gripping meter spades Lost their spring memory

Jaws spread out and not firmly connect to the full surface area of the meter blade creating air gap between meter spade and socket jaws

Corrosion on jaws corroding metal of jaws and impeding current flow

Contamination on jaws increasing resistance of current flow

Socket jaws are old and the metal is fatigued increasing connection impedance

Some sockets have steel jaws which can corrode easier

Socket jaws are loose and need to be tightened

Wiring to meter socket or socket jaws are damaged

Root Causes of Hot Socket Installations

3Example of a Hot Socket Root Cause

4 Have been around for many years Meters in the past have been subjected to hot socket

conditions until they heated up to the point where they failed

The utility found out about the event when a customer called in with an outage

Sensus is delivering a new solution to this old problem

Hot Sockets

5 The first goal is to detect high temperatures in the meter Meter temperature crossing a threshold Trigger alarm Meter opens its switch Rules allow for the creation of actions to be taken as a

result of an alarm received. Email, Text Message to designated utility personnel Different information types to appropriate persons

Detecting High Temperature