The document outlines the safe isolation procedure which involves identifying the point of isolation, locking it off with a warning label, testing with approved equipment to ensure no voltage is present, retesting equipment, and isolating secondary energy sources. It recommends seeking permission first if vital services could be interrupted. Key steps include locking isolation points, applying warning labels, thoroughly testing for voltage absence, and isolating backup power sources.

1. The Safe Isolation Procedure
There are industry-wide recommendations
on correct procedures in order to achieve
safe isolation. The following steps described
the Safe Isolation procedure.

2. Before starting the Safe Isolation Procedure,
remember to seek permission from a relevant
responsible person, because there might be
certain vital services that must not be
interrupted at any time. There might be a
permit to work system in place to which you
will need to comply.

3. • Identify the point of
isolation for the system
or circuit.
• Lock off
• Place warning label
• keep the key to the lock
with yourself.

4. • Select the correct and
mains approved test
equipment
• Ensure that it works
correctly by testing on
the proving unit.

5. • Test the outgoing side of
the means of isolation
(Main Switch, MCB,
Fuse, etc.) to make sure
it is dead.
• Depending on the type
of the supply you will
need to complete the
following tests:

6. • Single Phase installations
test to confirm that there
is no voltage between:
- Line and Neutral
- Line and Earth
- Neutral and Earth.

7. • 3 Phase installations test
to confirm that there is
no voltage between:
- L1 and L2
- L1 and L3
- L1 and Neutral
- L1 and Earth
- L2 and L3
- L2 and Neutral
- L2 and Earth
- L3 and Neutral
- L3 and Earth
- Neutral and Earth

8. • Re-test the test
equipment on the proving
unit.

9. • When isolating the main
source of energy it is also
essential to isolate any
secondary sources such as
standby generators,
uninterruptible power
supplies (UPS) and
microgenerators.

10. Safe Isolation workflow diagram
• The following workflow
diagram on safe
isolation is an excellent
resource that should be
part of every
electrician's tool bag.
• There is a Download link
to this at the bottom of
the page.

11. Best Practice Guide
The Best Practice Guide on Safe Isolation Procedures,
produced by the Electrical Safety Council in
association with leading industry bodies for the
benefit of electrical contractors and installers is a
downloadable booklet, freely available from the ESC
website. It is an excellent resource for electricians
and we highly recommend it. You can download it
using the link provided at the bottom of the page.