Question for you SureTest - Electrical Guru's

[DonTx]

I was inspecting a home yesterday and noticed that the Master Bathroom lights flickered just a little, like in an eye blink, whenever I plugged my ST into a Master Suite outlet. The "blink" would come just as the ST read out the volts.

Same thing today (both new homes) so I started experimenting with the ST. On today's home, the hall bath lights would flicker when I plugged the ST into an outlet in the hall.

I tabbed through the numbers on the ST and came up with these readings; #4 reading measured 1.4 - 1.7, #5 reading was 11 and #6 was .19. Other outlets showed 0 or close to it on #4 and #5

Can anyone shed some light on what these readings mean and/or what would cause these lights to "flicker" just as the ST was reading out?

Edit: BTW, the voltage drop was 5.4% on the hall outlet and about that or less on other outlets.

[Darren]

The Sure-Test (somehow) puts a load on the circuit. That is the reason of the 'dimming', the load is applied and the calculations (volts & voltage drop) begin.

It's the same timing as when you hold the GFCI test button; the circuit is supposed to trip the exact same time as the dimming occurs when the GFCI is not held.

Sound good?

Darren

[DonTx]

I figured the flickering was caused by the load the ST put on the circuit. What I can't figure out is why? It doesn't do it with all circuits.

The readings I noted on position #4 and #5 of the ST were higher than other outlets in the house, but I'm not sure what those settings are or what they mean. I'm thinking they have something to do with the flickering.

[Jim Katen]

Originally posted by Donald Lawson

I figured the flickering was caused by the load the ST put on the circuit. What I can't figure out is why? It doesn't do it with all circuits.

The readings I noted on position #4 and #5 of the ST were higher than other outlets in the house, but I'm not sure what those settings are or what they mean. I'm thinking they have something to do with the flickering.

Well, I don't know why the lights are flickering, but I can explain what #4 & #5 do.

#4 is the voltage potential between the ground and the neutral. There shouldn't be any. If there is, that means that you've got some current returning through the grounding wires, a common enough condition when grounds and neutrals are bonded in a subpanel or where there's a dryer with at three-slot connection. I can't imagine why this would cause the lights to flicker more or less when the Suretest does its thing.

#5 is just a measure of how much load is on the line when you're testing it. Maybe if there were already enough of a load on the line, the additional momentary load from the Suretest would cause enough of a voltage drop to affect the lights for a fraction of a second.

I dunno.

- Jim Katen, Oregon

[DonTx]

Thank Jim, you've explained those two functions a lot better than anyone I've heard before. Now I think I understand them.

Now, how about function #6, holding the button down while plugging the ST in? I've noticed that this function will trip AFCI's and GFCI's. I have the older ST-1D.