Ieee std 1159-1995, ieee recommended Practice for Monitoring Electric Power Quality

7. Application techniques 
This clause offers application techniques that can assure safe and effective collection of electromagnetic
phenomena events. It is neither intended to be a step-by-step requirement for conducting power quality sur-
veys, nor does it present an exhaustive listing of issues to consider. Familiarity with this clause, however,
will help ensure the safe collection of useful data.
This clause begins with safety considerations. Monitoring often involves intruding in some fashion upon
electrical circuits that have the potential to injure people and damage equipment. Steps for the typical moni-
toring techniques related to monitoring location, test equipment connection, threshold settings and program-
ming, and determining a monitoring duration are discussed.
7.1 Safety
The manner in which a disturbance monitor is attached to the circuit under evaluation may impact the audit
in areas other than the accuracy of the data being captured. It is imperative that the attachment of the sense
leads be made in a fashion that does not jeopardize the safety of site personnel as well as the integrity of
existing connections. While most hookups are temporary in nature and may not utilize the same practices as
for permanent installations, the National Electrical Code (NEC) [B2] and local codes should not be compro-
mised.
7.1.1 Hard-wired connections
Sense lead connections that shall be made in load center panel boards or junction boxes should be attached
in a manner that does not violate the listed use of the devices to which they are attached. This generally
includes returning doors, cover plates and access panels to their in-use position (i.e., closed, mounted with a
full set of screws, etc.). If panels must remain open during monitoring, adequate means shall be provided to
limit access to the area and inform others about the monitoring setup and the responsible on-site contact.
Leads may be connected to existing circuit overcurrent protection devices if the device is designed for the
attachment of multiple conductors.
Sense leads should not be twisted around existing wires or inserted in circuit breaker connectors that are
designed to receive a single connector. Alligator clips are totally inappropriate for this type of connection as
they can be easily dislodged and it is difÞcult at best to properly insulate or strain-relieve them.
An alternative to using existing screw- or clamp-type attachment points is to use an approved pigtail-type
connection. For example, pigtails should be used where sense leads must be connected in a panel board or

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IEEE
Std 1159-1995
IEEE RECOMMENDED PRACTICE FOR
36
junction box. To execute this type of connection, the power to the circuit should be de-energized; the
conductor to be monitored should be removed from its connection; a four- or Þve-inch pigtail of insulated
electrical wire rated at the same current-carrying capacity as the removed conductor should be installed in
the original connection; and then the pigtail, the conductor to be monitored, and the sense lead can be
connected together with an approved wire nut or fastener. This new connection should be taped to ensure
proper insulation and safety of the connection.