How To Prevent Electrical Hazards In The Workplace

It is vitally important to prevent electrical hazards in the workplace. Below you will find detailed information on how this can be achieved:

 

– Ensure the Electrical installation/electrical system meets codes and regulations.

– Conduct inspections to identify electrical safety deficiencies.

– Provide training for qualified.

– Report electrical deficiencies immediately.

 

To make an electrically safe workplace, the source side to the load end shall be safe. To explain the safe electrical system I will discuss:

 

– Information on electrical system

– Condition of the electrical system

– Maintenance and inspection program of the electrical system

– Lightning protection system

– Earthing system

– Emergency power system

– Worker training

– Lockout/Tag out

– Personal Protective Equipment – It may be helpful to read this article I wrote on electrical PPE here.

Condition of Electrical System That Must Be Followed

 

Overhead Service

    • Covered conductor.
    • Gooseneck bend at the top shall be used.

 

Energy Meter

    • Accessible to the authority.
    • Convenient height.
    • Protective cover except for the glass window.
    • It shall not be installed less than 1m above the ground.

 

Sub-station

    • The separate substation for load more than 50 K W.
    • Considering 80% load factor except for requirements of future expansion.

 

Location

    • Multi-storied building: lowest floor level.
    • Building complex/group of the building belonging to the same organization: separate building adjacent to the generator room.
    • The basement floor shall be avoided.
    • The floor level shall be above the highest floor level of the locality.
    • Suitable arrangements shall exist to prevent the entrance of storm or flood water into the sub-station area.
    • The minimum height of a substation room should be 3.0m to 3.6m depending upon the size of the transformer.
    • Need proper stairs (where required) at the entrance.
    • Foreign utilities (wet pipes) are prohibited.
    • The room shall be properly fire-rated.
    • Required firefighting equipment must be kept.
    • The substation room shall be properly illuminated.
    • Need proper room partition.
    • Need proper ventilation.
    • The minimum area of the substation room with different transformer sizes is listed below;

Capacity of transformer (KVA)

Transformer room area (m2)

Total sub-station area (with HT, LT panels &  transformer room but without generator)

1 x 150

12

42

1 x 250

13

45

2 x 250

26

90

1 x 400

13

45

2 x 400

26

90

3 x 400

39

135

2 x 630

26

90

3 x 630

39

135

2 x 1000

26

90

3 x 1000

39

135

    • Sub-station room shall be clean and free from dirt, lint, water, oil, combustible material, and debris.
    • An instruction board for first aid and artificial respiration shall be located.
    • Must have adequate security.
    • Required equipment and safety signage are needed.
    • All equipment in the substation room is efficiently earthed.

 

Transformer

    • Stormwater shall not enter the transformer.
    • The transformer shall not be installed on a combustible base.
    • The oil quality, of silica gel should be checked on a regular observation basis.
    • The transformer shall be lint, dirt combustible free. Otherwise, it may cause a fire.
    • The upper-lower part of rod-gap arresters shall be aligned.
    • Two-hour fireplace rating unless in an exceedingly high-rise building.
    • Four-hour fireplace rating if in an exceedingly high-rise building.
    • The transformer shall be installed in a separate room with a fire-rated wall and door.
    • Border with the lockable arrangement.

 

Boiler Room Requirements

    • The volume of the room for housing central heating boilers shall be at least 16 times the total volume of the boiler.
    • Any area or area housing boilers or alternative heat manufacturing instrumentality shall be separated from alternative areas by a minimum one-hour construction or by a minimum special separation of 3m (10 ft) wherever set exterior to the building.

Other Safety Factors

    • Proper and regular maintenance must be done.
    • The boiler should not be operated beyond its certified steam pressure.
    • Boiler logs must be kept in a boiler room and should be maintained properly.
    • LT/MDB/DB/SDB/SB/MCB, MCCB box/others:

Location: Sub-distribution boards shall be located as close as possible to electrical load centers.

Requirements: Distribution boards shall be installed within 2m from floor level.

Recommended Enclosure Sizes for MCBs and Fuses:

Dimension in mm

No. of MCBs or Fuses

Height

Width

Depth

350

390

120

Up to 12

480

390

120

Up to 24

610

390

120

Up to 36

740

390

120

Up to 48

 

    • Switchboards and/or distribution boards shall be metal enclosed with dead front construction.
    • Require at least 1m clearance in front of the panel board.
    • The distribution board shall not be erected above gas stoves or sinks or within 2.5m of any washing unit in the washing room or laundries.
    • Adequate illumination shall be provided.
    • Panelboards shall be properly grounded (earthed)
    • Panelboards shall be properly identified.
    • List and diagram shall be available.
    • The circuit must be drawn with a protective device.
    • Each circuit must have adequate ECC & neutral (if applicable)
    • Meters and other electrical devices need to be installed at the main DB.
    • Instruction of first aid & artificial respiration shall be kept near DB.
    • The color code of the cable/wire shall be maintained.
    • Color code rules:

Single Phase

Three Phase

 

 

Phase Conductor

(Line)

Red or

Yellow or

Blue

Line 1 Red

Line 2 Yellow

Line 3 Blue

Neutral Conductor

Black

Protective Conductor (Earth)

Green and Yellow

 

    • Cable color code is for the identification of conductors used in electrical installations.

Single Phase

Three Phase

 

 

Phase Conductor

(Line)

 

 

Brown

Line 1 Brown

Line 2 Black

Line 3 Grey

Neutral Conductor

Blue

Protective Conductor (Earth)

Green and Yellow

    • Switchboards and/or distribution boards shall be free of combustible material, dirt, and debris at the near and inner side.
    • Indications of overheating, overloading, or signs of burning shall be remediated.
    • At least one spare circuit must be allowed in the distribution board for every five circuits in use.
    • Sockets and Lights shall be used in a separate circuit.
    • No higher-rated circuit breakers with lower-rated wiring are acceptable.
    • All metal in the building shall be connected to the building earthing/ground system.
    • Junction boxes and other electrical devices shall be provided with covers.
    • Mechanical guards shall be provided for electrical equipment and wiring where necessary.
    • For buildings over six-story or 20m high, a service shaft is required.
    • Bunching cable/wire not allowed.
    • Looping is not allowed.
    • Phase separators must be provided between terminals on circuit breakers.
    • Electrical wiring and conduit shall be properly supported.
    • A cable socket/lug shall be used.
    • Splicing joint not allowed.
    • Wire in the panel shall be dressed.
    • Proper terminal connectors shall be used.
    • Cable trenches shall be properly covered.
    • Sufficient and graded rubber (insulation) mat shall be kept in front of the panel.
    • Ceiling rose shall be used to connect the tube light and fan.
    • Electrical handheld tools shall be of good quality.
    • Power and telecommunication cables shall be led separately.
    • Normal DB, light, etc not allowed in the chemical room.

Lightning Protection of Building

Whether a building needs protection against lightning depends on the probability of a strike and an acceptable risk level.

 

Earthing System

Two separate and distinct earthing connections are required for

    • Generator frame
    • Motor
    • Transformer
    • Energy regulating apparatus
    • Energy-consuming apparatus
    • Metallic pipe
    • Metallic shed etc.

 

Electrical Hazards Maintenance and Inspection Program

Regular inspection and maintenance programs shall be carried out to ensure proper installation. Some requirements are:

    • Periodical inspection and testing.
    • Periodical Inspection Resistance test (IR test).
    • Electrical switchgear annual basis inspection. Earth Resistance test (ER test).
    • Earth electrode resistance shall not exceed 1.
    • Calibration/validation of all types of meters.
    • Load measurement.
    • The transformer oil analysis shall be routinely completed.
    • Proper training.
    • Thermo graphic scans and hot point remodification.
    • Electrical measurement meters: Digital Multimeter, Clamp Meter, Insulation Tester, Earth Resistance Tester, Thermal Imager.

 

Leave a Comment