Electric dryer - thermal fuse question

How could such a device provide protection? You don't want a fuse "fusing" to a short!

Unless the thermostat is broken, how will this fix the problem? If the dryer has such a thermostat, and it opened, it most likely opened BECAUSE THERE WAS AN EXCESSIVE LOAD elsewhere in the circuit. And the OP has to find that, and fix it.

If it is what I am thinking about it is not a fuse at all. It is a thermostat inline with the motor and senses temperature to shut down if there is an over temp condition. Dryers have several in various locations. If the OP has one that is defective it may open prematurely. Take it out to test it and it cools off and resets.

Of course, I could be all wet. I can't see the wiring diagram and have no model info. It is unlikely that a real fuse would recover. Part of the fuse rating indicates the highest voltage a fuse is supposed to successfully open.

Charlie

Hi Mike

Opened and closed the breaker several times, of course. But what does this mean?:

Set the meter to AC 750v range. Closed the breaker. Tested black to neutral: no reading. Tested red to neutral: In a split second "FFFZZZZ!" and the wire inside the insulated test lead fried and shot out of the test probe.

Needless to say I didn't get a chance to check 120 to 120. 8-)

Did all the safety stuff right, as far as I know: Insulated (rubber sole) boots, still stood on a wooden frame instead of the concrete floor, had someone else on hand tripping the breaker, insulated test leads - of course. In other words, I came out of it uninjured.

Still, the circuit breaker didn't trip...

What does this mean? Ground fault problem somewhere in the 240v between the panel and the outlet? Want to know before the electrician comes in so we understand what he's checking and fixing.

Rick

Did you have the probe plugged into the Amps jack? I'm not sure how else the wire would have burned up like that, you may well need a new meter now though.

Non-sequitur. It sounds as if you had the probes inserted in the current jacks.

Nope. I checked it twice before testing. And since it was brought up I looked at the meter again - correct jacks.

Your reasoning wouldn't explain why it didn't 'zap' when testing the first 120v side of the 240v receptacle. I got no reading at all on the white and black side. (No fried test lead either.) It went 'zap' when I tested the white and red side.

Rick

But black to neutral might be little or no voltage. Maybe.

Regardless, voltage ranges have extremely high impedances. It should be "impossible" to pump enough current through them to blow up the wiring.

Was it set to read voltage or current? Likely current.

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st

he

I think he needed a new meter before he started!

OP, is that the only meter you have? (Er, had?) Starting to sound like the meter was defective!

"Mr. Land" wrote in news: snipped-for-privacy@e25g2000prg.googlegroups.com:

It's been sounding like the operator is defective....

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Huh?

Black-white should be 115 VAC Red-white should be 115 VAC Black-red should be 230 VAC

White-green or white to bare may be near 0 VAC>

Assuming it wired with proper color code.

If white-black was 0 V, then there is a problem. But sounds more like the meter was on the wrong range, connected wrong, or broken.

Yep, something is fishy....

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I personally don't mind checking voltages and so on - "always" double checking meter settings before hand - even if doing a "radio" or some other appliance. Going with what Sam mentioned - "Assuming" the wiring is to proper color code. There are a lot of wannabe Electricians out there - who don't know their butt hole from a hole in the ground. I can also wonder about some so-called "electricians". WHY? I've known of at least a dozen so-called "electrical fires" - occurring not too long after the building was "re-wired". Obviously - someone must have goofed.

This thread - due to "wiring issues" in the "box" - is starting to mirror the one about someone's TV set damaged by "alleged" faulty wiring.

I knew a "Mill" Electrician at one time. He had a weird way of wiring things - and most anyone who knew him would say that. I seen a sample of "Switch box" wiring he did once for a PA system. Man, what a rats nest. How it worked is beyond me - but it did. I'm glad I wasn't the one who had to replace it all - when it was done. The best thing there - would have been to take it all out and start fresh.

Yep, something is fishy, and I suspect the wiring in the receptacle. A few years ago, I had a dryer that kept burning out heating elements, the temp inside the dryer would get scorching hot, and if I didn't keep a close watch on it, would burn the clothes. Since the dryer was about 20 years old, I bought a new dryer. After a while, the new dryer started acting the same as the old one. Digging into the problem, what I found was that the 10ga wiring in the box was too short to fit properly into the receptacle. One of the wires was barely touching the receptacle screw. After a lot of tugging and cursing, I finally pulled enough of the wire into the box to make proper connections. Been working like a champ since.

If the OP's probe got zapped just by inserting it into the receptacle, I can only surmise that the receptacle was broken and the internal contacts were loose inside. Plugging the probe into the socket moved the terminals enough that they shorted.

At any rate, the solution is to replace the receptacle, taking lots of care for safety's sake, and be sure it's wired correctly.

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He said the wires to the probes melted. The *only* way this can happen is a short within the meter itself. Otherwise there's just no way to get enough current to flow, most DMMs have an impedance of 20 megohms.

Unless it was on a high amps range, which would have been shunted.

- Tim -

Well he also said the probes were plugged into the volts jacks, so either the meter is shorted, or he misread the labels.

Or he had it set to ohms... And the fuse was either bypassed, or never existed (like in most *cheap* DVOMs)

Most meters have several current ranges that _don't_ use the separate high amps jack.

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