Electrical Hazards

9 Ways to Verify Safety of Electrical Connections & Circuits

Date First Published on SafetySmart Compliance: January 28th, 2013
Topics: Electricity |

 The OSHA Electrical Standard 1910.303(b) requires you to keep electrical equipment “free from recognized hazards likely to cause death or serious physical harm” to workers. To comply, you must evaluate not just the actual equipment but electrical connections and circuits. Here are the 9 things OSHA says you have to check:

Make Sure:

1. Devices & Conductors Made of Different Metals

The different physical characteristics of dissimilar metals can create hazards that you need to guard against. Specifically, there are 3 things to check:

  • The material of the conductor used in devices such as pressure terminal or pressure splicing connectors and soldering lugs is identified and the installation and use is safe for that particular material;
  • Conductors of dissimilar metals aren’t intermixed in a terminal or splicing connector in which there’s physical contact between dissimilar conductors, e.g., copper and aluminum, copper and copper-clad aluminum, or aluminum and copper-clad aluminum (unless the device is identified for the purpose and conditions of use); and
  •  Materials such as solder, fluxes, inhibitors and compounds are suitable for the use and of a type that won’t adversely affect the conductors, installation or equipment.

2. Conductor to Terminal Parts Connections

Connections of conductors to terminal parts must ensure a good connection that doesn’t damage the conductors via pressure connectors (including set-screw type), solder lugs, or splices to flexible leads. (No. 10 or smaller conductors may be connected via wire binding screws or studs and nuts that have upturned lugs or equivalent.)

3. Identification of Particular Terminals

Make sure any terminals for more than one conductor are identified as such. Ditto for terminals used to connect aluminum.

4. Splices & Joinings

Verify that:

  • Conductors are spliced or joined with splicing devices identified for the use or by brazing, welding or soldering with a fusible metal or alloy;
  • Soldered splices are first spliced or joined to be mechanically and electrically secure without solder and then soldered;
  • All splices and joints and the free ends of conductors are covered with: i. an insulation equivalent to that of the conductors; or, ii. an insulating device identified for the purpose; and
  • Wire connectors or splicing means installed on conductors for direct burial are listed for such use.

5. Isolation of Electrical Equipment from Combustibles

Parts of electric equipment that in ordinary operation produce arcs, sparks, flames or molten metal must be enclosed or separated and isolated from combustible materials.

6. Marking of Electric Equipment

Make sure electric equipment is marked with:

  • The manufacturer’s name, trademark or other descriptive marking; and
  • Other markings giving voltage, current, wattage or other ratings.

Markings must be durable enough to withstand the environment in which the equipment is used.

7. Marking of Disconnecting Means & Circuits

Make sure:

  • Disconnecting means for motors and appliances are legibly marked to indicate its purpose (unless the purpose is evident); and
  • Each service, feeder and branch circuit legibly marked at its disconnecting means or overcurrent device to indicate its purpose (unless the purpose is evident).

Again, these markings must be durable enough to withstand the work environment.

8. Locking Capacity of Disconnecting Means

Make sure the disconnecting means can be locked in the open position.

9. Markings of Equipment Used in Combination with Each Other

Verify that use of circuit breakers or fuses complies with the series combination ratings marked on the equipment by the manufacturer. Equipment enclosures must be marked in the field to indicate such compliance with a legible marking that’s readily visible and states:

“Caution — Series Combination System Rated_____Amperes. Identified Replacement Component Required.”

Ensure Compliance with Electrical Equipment Rules

Go to the SafetySmart Compliance Electricity Compliance Center to get more help complying with OSHA electrical safety requirements: