The amount of resistance that a ground strap should have is 5 ohms or lower.
Sensitive equipment requires lower resistance values of 1 ohm or less for the ground strap and depend son the situation.
A lower resistance for a ground strap is better and indicates that there is a good electrical connection to the ground.
Higher resistance on a ground strap means that there is poor electrical connections to the ground.
The material of the ground strap and connection points also factor into the resistance.
You can use a multimeter to measure the ground straps resistance by placing one probe on the ground strap and the other probe on a good known ground point.
A ground fault can be measured in ohms using an ohmmeter and the reading of the ohms can indicate whether the ground fault is hard or soft.
A reading of less than 100 ohms indicates a hard ground fault.
A reading between 100 ohms and 100,000 ohms (100 KOhms) indicates a soft ground fault.
A reading of more than 100 KOhms may indicate a hard-to-measure ground fault or spurious measurements.
To test for a ground fault using a multimeter:
Turn off the circuit.
Set the multimeter to the lowest resistance (ohms) setting.
Connect the black probe to a known ground point.
Connect the red probe to the component in question.
A reading close to zero ohms indicates a ground fault.