[Hallb-engineering] Fwd: Lesson Learned "Implement a Conservative Approach when Working with Multi-wire Branch Circuits and Other Neutral Hazards- Mission Support Alliance, Hanford Site"
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Subject: Lesson Learned "Implement a Conservative Approach when Working with Multi-wire Branch Circuits and Other Neutral Hazards- Mission Support Alliance, Hanford Site"
Jefferson Lab Lessons Learned : Print Lesson
Implement a Conservative Approach when Working with Multi-wire Branch Circuits and Other Neutral Hazards- Mission Support Alliance, Hanford Site
Statement of Lessons Learned
Electrical workers at DOE facilities must be trained to a more
conservative approach than the commercial sector when working with
potential shared neutrals. Actions must be institutionalized to prevent
repeat events. A briefing or one-time training is only a temporary fix
and a set-up for repeating the same event in the future.
Discussion of Activities
While removing an old GFCI outlet, an electrician discovered two neutral
wires under one line terminal screw. When the electrician removed the
wires from the screw he noticed a spark as the wires were separated.
Separating the wires disrupted the continuity of the neutral circuit
causing one of the neutral wires to become energized. Work was
immediately stopped and the outlet was returned to a safe configuration.
The electrician�s actions were consistent with general industry work
The electrician did not recognize the potential for a neutral hazard.
The panel schedule did not indicate a multi-wire branch circuit. The
configuration of the wiring, with only two pairs of wires, did not
indicate a multi-wire branch circuit. The electrician, therefore, did
not treat the neutral as a potential neutral hazard. Due to the nature
of shared neutrals there was no voltage to detect until the continuity
of the neutral was disrupted.
Below are the consequences of the above event.They are provided for
information and discussion purposes only.
The electricians performed circuit verification and documented the
results in the work package.
Future actions to be taken:
1. Institutionalize training on shared neutrals in site electrical
training courses for electricians, instrument technicians and
controlling organization administrators.
2. Include text, in the Job Hazard Analysis Electrical Safety
Checklist, that a neutral wire may go hot when cut, voltage rated
PPE should be worn when cutting a neutral wire, and that a zero
energy check should be made before and after the wire is cut.
3. Attach Warning labels to electrical panels that are known to have
multi-wire branch circuits.
JLab Preventive Measures
(Jefferson Lab�s Subject Matter Expert has read and approved this lesson.)
In accordance with ES&H Manual Chapter 6200 Jefferson Lab�s Electrical
Safety Program, only qualified electrical workers are authorized to work
on energized equipment, and only to a limited mode and class.Only
licensed electrical tradesman are authorized to work building�s
1/21/2016 11:22:20 AM by Bailey, Mary Jo
Submitted to those with SAF104: LOCK, TAG, AND TRY and
SAF603A: ELECTRICAL SAFETY AWARENESS training
Summary Lesson ID: 930
Doc ID: 2016-JLAB-930
Safety Related: YES
Originator: Bailey, Mary Jo
Issued: 1/21/2016 11:18:35 AM
Approved By: Bailey, Mary Jo
Approved On: 1/21/2016 11:22:20 AM
Contact: Gerald Whitney 509-372-2166
Queued Emails: 0
Sent Emails: 0
Viewings: 1 times Attachments
* DOE - GFCI Outlet.pdf
* Lock, Tag, Try
* SAF104: LOCK, TAG, AND TRY
* SAF603A: ELECTRICAL SAFETY AWARENESS
* *Division Safety Officers (DSOs)
* *Safety Wardens
* *DOE Notification
* *ESH&Q Liaisons
Do you have a lesson learned you would like to contribute? Contact the Lesson Learned Coordinator .
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