When inspecting and testing on a 3-phase board (or even a single phase), one of the items of equipment that you may have to deal with is a DOL starter. Typically, it will have 3 phases going into a contactor and 3 phases from the other side of the contactor feeding a motor or other machine or socket outlet.
I had a candidate come in for his 2392 the other week and when I advised him to test his continuity using the Method 2 (wander lead or R2 method) for his assessment to save time, he said that as he had been shown the R1+R2 test method, that was the method he would use.
Without doubt the hardest tests to carry out accurately are the continuity tests. The maxim here is ‘repeatable and consistent results’. So, let’s look at some of the things that could adversely affect your results.
Polarity is one of those concepts that everyone thinks they understand, but on closer questioning few do, leading to very few electricians understanding why they are testing for it, the consequences of incorrect polarity and how we check it.