Basic testing equipment for electrical circuits and receptacles.

As professional sanitarians, we are obligated to examine all aspects of an environment to prevent both illness and injury. Injury prevention includes basic electrical safety. None of us would overlook a frayed electrical cord, a badly chipped or broken receptacle, an electrical hot spot, or an obvious potential short circuit during our inspection duties. So why not go one step further and perform those few tests that would ensure minimum electrical safety?

We found that we could look at four parameters of electrical safety in the most obvious places, using three inexpensive instruments. The four safety parameters are as follows:

* current flow and potential leakage;

* correct internal wiring (hot neutral and grounding conductors must be connected to the appropriate receptacle contacts);

* the ground fault circuit interrupter (GFCI) (the trip level of portable or wired-in GFCIs must be within a 2-to-7-milliamp (mA) range; and

* contact tension (the holding force of each contact during extraction of the test plug must not be less than 4 ounces).

The three instruments are as follows:

* AC sensor,

* GFCI/receptacle circuit tester, and

* receptacle tension tester.

In all, the instruments amount to an investment of about $100.

We have included this trio as a standard addition to our inspection kit. The instruments are small, portable, rugged, simple to operate, and extremely serviceable. Made by several manufacturers, they are available through your local electrical equipment and supply wholesaler.

AC Sensor

This instrument is probably the most versatile of all. It is a little larger than a pen and fits easily into a shirt pocket, next to the dial thermometer. The AC sensor is a UL-listed, handheld device for determining the presence or absence of AC voltage in insulated wires, wall receptacles, junction boxes, switches, and any other voltage-carrying electrical systems. No contact is required for its operation, and current flow is not necessary to locate voltage. Simply touch the plastic probe tip to a connection point or move it along an insulated wire. If AC voltage is present, the LED light in the probe tip will glow bright red. Use the instrument to check equipment such as slicers, mechanical can openers, timers, and any other kinds of food equipment before you inspect them. In our institutional practice, we use the AC sensor constantly, to monitor for live current and electrical leakage in numerous small appliances, lights, and switches.

The AC sensor uses two AAA batteries, which should power it for about a year. As with any instrument, make it a safety practice always to test proper operation on a known live circuit before use.

Ground Fault Circuit Interrupter/Receptacle Circuit Tester

The test instrument of choice is a combination GFCI/receptacle circuit tester that can be used on any standard or GFCI-protected three-wire receptacle or any remote- or portable-breaker type of GFCI. The circuit tester has a simple arrangement of neon indicator lights (red, amber, and clear), which provides a convenient means of testing three-wire, 115-volt, AC single-phase, polarized receptacles. It shows proper connection of the ground wire, correct polarity, or fault in any of the three wires; each condition is clearly labeled on the test unit.

If the instrument shows that the wiring is correct, depressing the test button then tests the GFCI. If the indicator lights go out, the GFCI has tripped properly. If the lights stay on, the GFCI receptacle is defective, the breaker is defective, or the ground and neutral are reversed.

When you insert the unit into the receptacle, you automatically test for minimal leakage current (1.9 mA). If the unit trips the GFCI before you depress the test button, either there is a 3-rna leakage between the breaker and the receptacle, or the GFCI trip level is set at less than 2 mA. If problems are noted, a qualified electrician should be summoned to check the entire circuitry and make any necessary repairs.

Receptacle Tension Tester

Contact tension affects receptacle performance both electrically and mechanically. The forces with which the spring contacts of a receptacle grip the blades of the attachment plug ensure reliable low-resistance electrical connections. If contact tension is insufficient, high resistance in the hot or neutral connections can cause internal heating of the receptacle. Loss of ground contact compromises the safety of the equipment. Electrical considerations aside, sufficient contact tension is important simply to prevent the plug from coming out of the receptacle when not intended.

Contact tension should not be so great, however, that the plug cannot be easily inserted or withdrawn. Proper contact tension of the plug receptacle serves as a mechanical fuse. When someone trips over a line cord, the accident should simply pull the plug out of the receptacle instead of pulling down the equipment or severing the line cord in some way. Contact tension that is too high does not provide this protection. A mechanical test of tension is adequate to show that the electrical contact resistance is sufficiently low and that the receptacle is mechanically functional and safe.

The receptacle tension tester, which is an adaptation of a simple spring scale, provides quantitative data on contact tension. The most common unit measures the tension in ounces and meets National Fire Protection Association standards for testing outlet tension. The unit has strong stainless steel blades that can be used on both two- and three-prong outlets. One end of the instrument has a round ground prong, and the other end has two plug blades that operate independently of one another. When the blades are inserted into the receptacle and withdraw. n, the force needed to withdraw each blade is read on the scale. At least 4 ounces of contact tension is required for safety in most applications. Hospital-grade receptacles require 24 ounces for neutral and hot blades and 4 ounces for the ground pin.

For information on how to obtain any of these products, please write or fax your request to Tools for EH, NEHA, 720 S. Colorado Blvd., South Tower, #970, Denver, CO 80246; fax [phone].