There are many occasions when temporary power connection is required, and there will be a temptation to make do with something on hand. Often, this solution will be considered out of expediency due to cost constraints, but can result in an un-safe work environment. Temporary does not mean “quick and easy”; it means it will be used for limited periods of time.
Article 590 of the National Electrical Code covers the requirements for the construction and operation of safe and approved temporary power equipment. It also describes the “shortcuts” permitted for the temporary power classification. However, all temporary power must adhere to rules and regulations governing the electrical rating and protection of permanent power installations. No shortcuts permitted here.
If a single feature were to be selected as representative of temporary power, it would be the flexible power cordset. The temporary power classification permits this power distribution shortcut. This provides the flexibility to provide power to various areas of the worksite by means of flexible cable, instead of requiring the wiring to be protected inside rigid conduit as found in permanent installations. Flexible temporary power distribution still requires branch circuit protection, usually in the form of a GFCI breaker (Ground Fault Circuit Interrupter). The protection requirements for temporary power deviate slightly from permanent installations, in that GFCI protection will be required for all 125V, single phase circuits of 15A, 20A, and 30A capacities where these circuits will be providing power to handheld tools and equipment.
Another distinctive feature representative of temporary power would be the power distribution box. This item provides the enclosure to house the temporary power circuit breakers and the cordset receptacles. This component will be positioned centrally, in order to minimize flexible cordset lengths and to reduce the tangles and clutter that can occur with unmanaged power connections. These temporary power shortcut features play together to provide a safe and efficient system for worksite power distribution.
To insure a safe and time efficient worksite, the following simple rules should be considered:
- Use tested and certified temporary power components that have been designed, built, and tested to established construction and safety standards.
- Use only tested and certified flexible cordsets of appropriate gauge and length.
- Use only single length cordsets; do not interconnect or daisy chain cords.
- Avoid the use of multiple circuit power taps if possible. Power taps increase the likelihood of overloaded circuits and create excessive cord tangles and clutter.
- Once a day or once per shift, manually test each GFCI circuit breaker or receptacle to insure the proper function of this circuit protective device.
- Route flexible temporary power cordsets around or away from areas of high foot traffic or where equipment is being moved frequently to prevent tripping of worksite personnel or physical damage to the flexible cordsets. Where cordsets must cross these areas, cable protectors are recommended.