Grounding Tester
#1
02-24-03, 10:48 AM
Grounding Tester
In general how accurate are those yellow 3 prong testers. The ones with the two yellow lights & one red light. When just the two yellow lights go on supposedly your correctly grounded.
#2
02-24-03, 11:10 AM
Accurate, Well sort of ya/no. Do I use one? Ya. Inspectors do as well.
Is there a ground when the light comes on, Sure. Is there a good ground ? Is the ground per code ? Is the ground going to hold under a short ? Answering these questions then no it's not accurate.
Is there a ground when the light comes on, Sure. Is there a good ground ? Is the ground per code ? Is the ground going to hold under a short ? Answering these questions then no it's not accurate.
#4
02-24-03, 11:38 AM
Member
These testers are incredibly simple, and thus perform reliably. It's just three simple voltage testers in one case. The three lamps are wired hot-to-neutral, hot-to-ground, and neutral-to-ground. In a properly functioning receptacle, the first two should light and the third should not light.
The biggest caveat comes when you have an open neutral. Because other loads may be present on the same circuit, the tester often incorrectly reads "hot/ground reverse" rather than correctly showing an "open neutral" reading. The hot/ground reverse indication occurs when both hot-to-ground and neutral-to-ground have voltage. The tester thinks that this means that the ground is hot. But it is really because both the hot and neutral are hot.
The biggest caveat comes when you have an open neutral. Because other loads may be present on the same circuit, the tester often incorrectly reads "hot/ground reverse" rather than correctly showing an "open neutral" reading. The hot/ground reverse indication occurs when both hot-to-ground and neutral-to-ground have voltage. The tester thinks that this means that the ground is hot. But it is really because both the hot and neutral are hot.
