The "Stitt Tester", Ground Circuit Impedence Tester by BWI Eagle

Electrical Grounding 101:

In most industries, electrical equipment is housed inside metal enclosures. If a power conductor accidentally makes contact with a metal enclosure which is not properly grounded, the enclosure becomes energized, which could result in serious injury or even death to anyone who touches it.

Also, in many cases the protective devices such as fuses and circuit breakers will not work if the equipment does not have a good ground circuit. A poor ground circuit may have too much resistance, which will not allow enough current to flow to cause a fuse to blow or a circuit breaker to trip. In this situation, the devices installed to prevent persons from getting shocked will simply not work.

Why should I bother testing

ground circuit resistance?

To make sure the equipment is safe to touch.
To make sure the protective fuses and circuit breakers will work.
And, it’s the law!

What’s wrong with the way it’s done now?

The most popular method presently used involves temporarily installing an external wire from the power source to the equipment being tested. In many cases this wire must be quite long, and installing it often puts the person doing the test in the precarious position of having to climb on high equipment while pulling the wire required to do the test.
The present method is very inaccurate. The resistance reading taken by an ohmmeter is very much influenced by the resistance of the contacts where the meter is connected.

So, what's the solution?

The EAGLE

STITT

TESTER !

With the Eagle Stitt Tester, you don’t need to install a temporary wire. It’s easier, and safer to use.
The Eagle Stitt Tester is very accurate. It measures resistance to 1/10 Ohm!
The reading is not affected by the contacts’ resistance.

Why can’t I just use my OHM Meter?

You can – IF the ground wire you are testing is short enough that the OHM meter can reach both ends of the wire. In most cases, however, the wire is quite long. Common thinking is that one could simply short one end of the ground and take the OHM reading at the other end. When that is done, the OHM meters reading is actually a combination of the ground resistance AND the second wire that you shorted to the ground, thus making it impossible to know the true ground impedance! One cannot assume that the reading should be equally divided to determine the resistance. The Stitt Tester utilizes a patented method of current and voltage that differentiates between the ground resistance and the return wire being measured, thus displaying only the true ground wire impedance on the display.

How does MSHA feel about testing ground conductors?

In 30CFR 56/57.12028, MSHA states:

The intent of this standard is to ensure that continuity and resistance tests of grounding systems are conducted on a specific schedule. These tests will alert the mine operator if a problem exists in the grounding system which may not allow the circuit protective devices to quickly operate when faults occur.

also:

…..numerous fatalities and injuries have occurred due to high resistance or lack of continuity in equipment grounding systems.

and:

Operators shall conduct the following tests:

equipment grounding conductors – continuity and resistance must be tested immediately after installation, repair, or modification, and annually thereafter….

FEATURES:

Easy to Use

Simple, Fast, One-Pushbutton Operation
Digitally Displays Accurate Reading in Seconds!

Accurate

Measures Resistance to 1/10 Ohm
Resistance Measurement NOT AFFECTED by Contact Resistance
Measures the TRUE Resistance of the Ground Circuit

Self Powered and Portable

Operates on AA Batteries with Low Battery Indicator
Compact, Hand-held Size and No Lengthy Wire Installation

Unique

Patented Measurement Device and Method (U.S. Patent No. 7,068,040)