My on off switch is melting. Measured 16A at the first heater element and only 7.5 at the second. What is causing this?

[ectofix]

Crescor makes a vast array of heating cabinets in many configurations.  To address an electrical problem (especially over the internet) – most certainly requires a schematic.

Your model number isn’t an exact match to any equipment listed on Crescor’s website, so can’t find a manual.  Here’s what’s listed in alpha-numeric order: Cabinets-hot Manuals 

 

Since I’m not there looking over your shoulder, I do not know how you’re going about in taking your amp draw readings.  It’s very important to know what wires you’re reading and what to expect it SHOULD be reading.  The way you wrote it, you tested at the actual wires to the elements.  I gather that there are TWO elements connected in parallel then?  From what I can interpret from your figures, looks like 16a is the current draw through a common leg for the two elements – which sounds normal for a 120v cabinet (you didn’t say what voltage unit you have).

Your 7.5a reading at the second element appears to have been gotten from a wire supplying JUST that one element – which also sounds normal.

 

You said the switch melts “prematurely” – which confuses me.  When is the switch SUPPOSED to melt?  

 

 

I take you replaced the switch and the new one turned crispy too?  Did you replace the wire terminals?

Usually when a switch melts, it’s due to a poor wire connection to it.  I recommend replacing those wire terminals.  When you do so, cut the wires back until there are clean, untarnished, un-oxidized wire strands.  If that’s not happening, then replace the wire(s) with new hi-temperature wire of a suitable ampacity.

[olivero]

Yeah, like Ectofix mentioned.

 

Not sure what you mean when you say iuts melting, is the whole thing a blob of blastic or the back of the switch holding the spaces? Its most likely a loose connection, which would also explain the reason its happening again. I started soldering all my crimp connections because of things like this, drives me nuts.

 

IF you have a thermometer infrared gun or a thermo camera you can try pointing it at the hot and neutral leg on the switch and see what they are, if its a camera, you will see it easy. If its a thermometer, it will show but its little difficult to get it right, but if you just measure the temps of the different connections, you can narrow down your problem. I have done this becuase of a similar problem and it worked in the end, found the netural wire space being 260* F when the unit was on which is a bit toasty.

[fixbear]

16 amps sounds a bit high. Look at your rating plate for wattage. Anything over 1200 watts @120 volts would require a special circuit and plug. Even at 208 or 230 your wattage shouldn’t be more than 1800 watts. This means that the total load, (fans, lights, heaters) would be about 10 to 12 amps. If you have a plug with ond blade vertical and one horizontal at 120 volts it will be 20 amp rating and a higher wattage is possible. If at 220 volts and both blades are horizontal it will be 20 amp and a 3600 watt ability..

 

   Anytime you have a higher load than that the usually use a relay for switching it. It is very hard to make a flat toggle switch with a rating of more than 15 amps. I have seen 30 amp models as a straight toggle,, but they are very pricey and hard to come by.

[buddy-moore]

Price for crescor 30a toggle $112 part#cre0808-087-K

 

just in case this is that what it needs. Hopefully the thermostat isn’t running away or like above the connections are bad. 

[badbozo2315]

> When is the switch SUPPOSED to melt? 

 

Why, just about a week out of warrantee, silly tech. 

[ectofix]

fixbear wrote:

 

16 amps sounds a bit high. Look at your rating plate for wattage. Anything over 1200 watts @120 volts would require a special circuit and plug. Even at 208 or 230 your wattage shouldn’t be more than 1800 watts.

 

Oh, contraire…fixbear.

There’s no chance of catching the knuckleheads that do that.  There’s just too many knuckleheads.

 

So, with some attempt at intervention (some say-so) with the purchasing of banqueting carts, we (our supervisor) has tried to be in-the-loop when that SAID department’s purchasing office goes to order new banqueting carts.

 

Don’t ask “How’s that workin’ for ya?” 

Hey.  We tried.

[fixbear]

That’s exactly what I’m saying. Above 1200 watts one has to have a dedicated outlet, circuit. with a 20 amp receptacle. anything less will create tripps and low voltage circumstance which causes higher amps and more heat to components like switches. Well designed units will use relays for load switching.. Not the thermostat or switch directly.

    As for the switch design for that high of amperage, it would have to have silver contacts instead of bifurcated.to have any reasonable service life. This alone makes cost quadruple for the switch. Like to see a old switch from Crescor to cut it apart to see. Bet they aren’t silver or gold. There is a lot of items coming into the country now that are inferior to the original spec’s. I bought a dozen fan motors last mouth that were all garbage. They were the original make and model, but have open armatures. Should have been found in QC test. Vender refuses to take them back, as they are electrical. Just what we all love,