Can somebody tell me is a MOV (Metal-Oxide Varistor) has a line and load side or if can wired in either direction?

I've googled like mad and can't find out...

Pete

It takes AC, and as such, can be wired in either direction.

Hi Matt,

That reply worries me. When you say "it takes AC" --- ok. But so does, say a relay -- but that relay needs to have the line side on the COM and the load side on the NO. Making there a right and a wrong way to wire it. So your saying that this is not the case on an MOV?

I always worry when people say that "AC" can be wired either way. Reminds me of people wiring their house light switches and putting the switch on the white wire and then saying, "Ah, it doesn't matter, it's called alternating current for a reason" - DOOOOOOOOOOOOOOH!

Thanks for clearing this up for me... I've never used an MOV before and just want to make sure I got it right.

Pete

Got it. Matt -- you're right on the MOV -- bi-directional. No polarity at all...

But I'd still like to better understand it all.

Pete

Electrically, there is nothing wrong with switching the neutral. In fact, if the line were balanced, there would be no neutral and no reason to put the switch on one side v. the other. You simply don't want to get shocked when changing a bulb.

Same for a relay. It doesn't care which side of the contacts have the power and the load. In an AC circuit, there is no way for the contacts to know.

Matt -- We'll have to agree to disagree on this one.

But I do appreciate your help, very much.

Pete

Obviously, you've missed the thrill of having the piss knocked out of you while pulling service on a disposer or dishwasher that had the neutral switched instead of the hot. The national electric code is there for a reason.

__________________
Never a dull moment at Berry Hill Farm.

I haven't.

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No matter how many times you explain it to me, I'm still right.....Surf-n-Turf

Trust me, I have. By "electrically," I mean for the circuit to function properly. Of course we want it to be safe.

If you 'switch' the white wire to an appliance or light you are running the hot or black lead to the appliance. This means that when you are working on the appliance and you are grounded, which you are most of the time, and touch the black lead at the appliance you will now complete that loop to ground and pop goes the weasel.

Guess thats why they say switch off the power 'at the breaker' before begining ... Bzzzttt!

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

With the hot wire on COM the NO wire will be hot when the relay is on, but as others have said, if you reverse the line and load wires the switch on the relay will work just fine.

Now, if you are switching 120VAC in a house, BOTH the COM and NO wires have to be color-coded as "hot" using any color other than White or Green.

Same for manual light switches, where both sides are usually black wires, or the white wire in the 'switch leg' has been taped or painted black in the switch box and in the light fixture box.

BTW, I changed a light fixture in the ceiling that had the white (neutral) switched. That particular fixture worked great for 20+ years, but it got me all 'tingly after I removed the fixture, undid the wire nuts and grabbed the now bare black wire thinking it was off

Now I use a proximity voltage detector that lights up and beeps if the tip gets near 120VAC. Ah, older and wiser!

PS - 120VAC is not as bad as an electric fence, but that's another story...