Seven steps that save lives//
While we usually focus our weekly technical releases on practical assistance for today’s engineers, nothing is more important than understanding how to work safely.
As an example of electrical safety procedures, we will discuss the safe working procedures used by HV field technicians – the ‘Seven steps that save lives‘. These steps are in line with common standards for safe working procedures. It is recommended to do a risk assessment prior to carrying out any electrical job.
The step order can vary according to the procedure used (for example issuing permit to work):
- Identification of the work location
- Disconnection and securing against reconnection
- Protection against any other live parts
- Special precautions close to bare conductors
- Proving the installation dead
- Carrying out earthing and short-circuiting
- Issuing a permit to work
1. Identification of the work location
Identify the right work location and mark it clearly. The work location should have appropriate access and lighting. Non-authorised persons shall be restricted from entering the work location.
2. Disconnect and secure against reconnection
Disconnect all possible points of power supply. Secure the reconnection by means of a lock out and tag out procedure to ensure that electric equipment does not accidentally come alive. Take special care with transformers of which the secondary may be alive.
3. Protection against any other live parts
Put formal warning notices on panels or cabins you are not working on. Additional physical barriers must be applied (locks etc.) when live equipment is exposed. Recheck that you have the correct point of work.
When multiple cabinets are open you might by accident start working on the wrong cabinet.
4. Special precautions when close to bare conductors
There might arise a situation where you are working near potentially live parts, or there might be a situation where you can accidentally touch live parts when putting up safety barriers.
Take special precautions (insulation gloves and or safety mats), especially if you are within a meter of a live connection. Take very special care on a moving vessel as the ship may suddenly start rolling, so never use a safety stool as is a standard practice ashore.
5. Proving the installation is dead
The installation needs to be checked with appropriate testing gear. Test the instrument as for proper functioning first. Then verify with the test instrument that the installation is dead. Recheck the test instrument, only then you are sure your installation is dead.
6. Carrying out earthing and short circuiting
Earthing makes the installation free of residual charges and short-circuits the system in case of a fault current. Use only equipment designed for this purpose.
7. Issuing a Permit to Work
No work should be started under any circumstance before a signed and fully authorised permit to work has been issued. No job is too urgent that safety should be compromised always ensure the 7 steps have been followed by yourself and your colleagues.
Source Reference: High voltage safety by ANTWERP MARITIME ACADEMY
Source Reference: Electrical Engineering Portal (EEP