While using the metalic condiut for the ground is an accepted practice, I personally do not like it.
The above incident is a prime example of why. Have seen and measured current up to 15 amps on conduit (20 Amp Circuit breaker). The breaker does not trip because the neutral has failed and the conduit has a high enough impeadance not to allow the breaker to see a fault. The reasons for the too high impeanance are many and include loose fittings, corrosion, and conduits that have come apart, even saw one repared with PVC. IMHO it"s better to pull a ground wire.
Testing does help. But in this case a lost time accident followed by a loss of job was a CYA on the part of the company. It does nothing to prevent another employee from making the same mistake. [Linked Image]

[This message has been edited by nesparky (edited 06-14-2004).]

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