Burnt electrical outlet and plug

*The circuit may be rated for 20 amps, but the receptacles and plug are not. Change them both to 20 amps and measure the actual current draw.
Reply to
John Grabowski
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That is what I think also. That is an after market plug (note the screws holding it together). It was not assembled correctly with a poor connection on the ground side. Replace it and the now damaged outlet.

You can always feel the plug and see if it is unduly warm, always a sign of a poor connection.

Jeff

Reply to
Jeff Thies

Don't assume a 30A rating requires a 30A plug. That rating is the maximum input current, and you can absolutely change the plug to a lower rating if the load on the conditioner is less than full load. The circuit protection is at the panel feeding the receptacle, so if that receptacle is on a 15A or 20A circuit it is fine. If the load is too high the breaker will trip.

Reply to
Pete C.

What kind of power conditioner? Big sucker with a (constant voltage) transformer in it? Note the posts about reactive loads (more apt to arc I believe). All that means for you is a better plug and socket, with the original fault lying in the plug. And perhaps do away with the conditioner if it is a constant voltage type and your voltage is tolerable.

Jeff

The input to the power conditioner shows it is rated up to

Reply to
Jeff Thies

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If it is a high resistance connection (which it may well be) there is no arc. One may develop later.

If there is an arc, it is a "series" arc. The original AFCIs won't detect it; they need an arc of around 50A (line to neutral or ground). The AFCIs installed 2008 and later can detect a series arc. AFCIs have only been around since 2002 and only for residential (this is office). But wait a few years. Required use is creeping like a slow plague in every NEC revision.

Reply to
bud--

Look at the pictures. Wouldn't you agree the breaker didn't trip?

Reply to
Tony Miklos

I hate to believe someone actually might not replace the outlets after they have been overheated so bad. The connection will surely be corroded and lost most of its spring tension.

Reply to
Tony Miklos

Nowhere that this kind of outlet is used is it legal for a non- electrician to replace outlets or plugs in an office or workplace. Have an electrician come in and replace both.

If you don't believe me, ask your insurance agent. Better him than the adjuster who comes in after something burns down.

I presume the reason you -- er, "someone" -- put an aftermarket plug on the cord is because the equipment came with a 30A plug, probably a twistlock. You may think that you've loaded it lightly enough that it won't draw more than 15A, but you may be wrong. Have the sparky quote on a proper 30A circuit installation while he's there.

If you do put it all back together in a 15A config, get yourself a Kill-A-Watt or other current monitor and find out what you're really drawing. If it's more than 12A continuous, you should not be on a 15A circuit. Some offices are wired all 12-gauge even on 15A circuits; if that's the case, depending on length and local regs, your electrician may be able to swap in a 20A breaker and T-slot receptacle.

Chip C Toronto

Reply to
Chip C

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Your outlets are 15 amp, not 20. The correct outlet will have a T- shape plug hole on the hot side. If the breaker is 20 amp and the wiring is 12 ga, somebody really screwed up.

Joe

Reply to
Joe

Why do you believe that he needs 20A outlets? The appliance obviously has a

15A plug on it, so it's not intended for more than 15A.
Reply to
krw

We don't know what size breaker is on the circuit. We don't know what the actual load amperage on the circuit is. It's entirely possible that a bad connection caused overheating of the contact at well below even a

15A load.
Reply to
Pete C.

I know that. Are you confirming what I wrote or disputing something? Read the last sentance of the post up a couple levels.

It reads: If the load is too high the breaker will trip. So if the breaker didn't trip, then maybe, just maybe someone is wrong when they say "a 15 or 20 amp circuit is fine". Maybe if it had a 30 amp outlet it would have made a better connection and never happened?

Reply to
Tony Miklos

It looks like an after market plug. We know little about the power conditioner except that it is rated at 30A. Possibly something like an RV plug was on it at one time (and what would you plug that in to!). But I'm just speculating...

Jeff

Reply to
Jeff Thies

In the past I have changed 30A plugs on a UPS out for 20A plugs, since the application had the UPS operating well below it's maximum ratings (mostly sized for run time). This was perfectly safe since the 20A receptacle was protected by the 20A circuit breaker, so if someone improperly added loads to the UPS the breaker would simply trip.

Receptacle contact areas don't dramatically increase with current rating. Yes, a 60A contact is notable larger than a 15A one, but there isn't a lot of difference between a 15A and a 30A in many connector styles (twistlock in particular).

The point here is that this is likely the result of a loose connection in the plug, and nothing else.

Reply to
Pete C.

I'd further speculate that it's probably just a case of pulling the plug while something with a large xfmr was drawing high current. Or, since this looks like a non-professional job, a wire internal to either plug or socket was touching gnd or neutral and it burnt away the short for them. Either way, it's not to code, is an OSHA violation and IMO wasn't installed by anyone knowing the fire or electrical codes.

HTH,

Twayne`

Reply to
Twayne

Since non-residential wiring is often stranded wire, that's a very good possibility.

Reply to
Twayne

It is a 20 amp receptacle according to the OP, and the device (still has not been established white kind of "conditioner") is rated at 30 amps.

It NEEDS a 20 amp plug. To handle up to 20 amps input current.

If it is a Ferro conditioner, that means it's good for about 15 amps out. They are quite effective heaters.

Reply to
clare

Uhh, it's the return path (ckt completion) for the Hot! It's the Earth ground that should have no current in it.

Wow; what's you do, rewrite the physics of electricity?

Reply to
Twayne

Not obvious at all. I could put a 15 amp plug on a 2 HP table saw.

Reply to
clare

The wire and connectors must be capable of carrying 80% of the load of everything on that ckt breaker. Since it's a 15A plug/receptacle and one piece of equipment is 30A I'd have to surmise they're using a time-delay breaker for one, that lets them slip by without popping the brkr, but : It is NOT to code! OSHA would have a field day with it, too. As would NFPA. I'd be interested also in what gage wire is being used to the box and to the other components drawing current? Sounds like a pretty dangerous place to work to me.

HTH,

Twayne`

Reply to
Twayne

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