restaurant cooking equipment conductors insulation melting

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benmin

benmin

Senior Member
Location
Maine
Occupation
Master Electrician
Have 2 steamer units at a restaurant where the insulation on the conductors entering the units has melted off. it is melted about 4 inches where the connection (wire nuts) is to where in comes in from the FMC. I saw this at another restaurant about a year ago on a broiler. Ran new conductors and and assumed it was a bad connection that was the cause. Now that I've seen it a few times, I wonder if it is caused by something different. Anyone run across this before?
 
Run some high temp conductors in the flex, and don't use standard "wire nuts" to connect either as most are only rated to about 105C.

I'd go with at least 150C conductors. Supply house likely has something, if not go to a commercial appliance service center/parts store.
 
Ditto, your probably not aware or paying attention to the sticker inside the electrical compartment or instructions that states what temperature of wire should be used to connect the equipment. THHN is only listed to 90*C some heating appliances require 105* or 150*C conductors.

Now that we've discussed this it has me wondering, does it state anywhere the minimum length of say a whip with higher temp conductors has to be before connecting to a lower temp conductor?
 
I wonder the minimum whip length also. If the cooking appliance requires higher than 90c conductors, in this case, it would be easier to add a jbox at the end of the fmc and extend with high temp wire
 
mopowr steve said:
Ditto, your probably not aware or paying attention to the sticker inside the electrical compartment or instructions that states what temperature of wire should be used to connect the equipment. THHN is only listed to 90*C some heating appliances require 105* or 150*C conductors.

Now that we've discussed this it has me wondering, does it state anywhere the minimum length of say a whip with higher temp conductors has to be before connecting to a lower temp conductor?
Click to expand...

Anybody know?
6"---- 1foot-------2feet--------3feet---------6feet. Has baffled me for a while just like some Walpack fixtures require higher temp supply conductors. So do you put a box behind the fixture with higher temp wires then 6" from that one have another j box where those can attach to? Usually see just THHN attached and usually burnt to a crisp.
 
mopowr steve said:
Anybody know?
6"---- 1foot-------2feet--------3feet---------6feet. Has baffled me for a while just like some Walpack fixtures require higher temp supply conductors. So do you put a box behind the fixture with higher temp wires then 6" from that one have another j box where those can attach to? Usually see just THHN attached and usually burnt to a crisp.
Click to expand...

Hot air rises, so the temp above the appliance will be higher then adjacent to or below the appliance. How much high temp "whip length" is needed will depend on those factors. Wall pack fixtures with too low rating supply leads - just deteriorates insulation within the fixture in most instances. But a ceiling mounted fixture with a junction box behind it may reach high temps in the junction box as well.
 
kwired said:
Hot air rises, so the temp above the appliance will be higher then adjacent to or below the appliance. How much high temp "whip length" is needed will depend on those factors. Wall pack fixtures with too low rating supply leads - just deteriorates insulation within the fixture in most instances. But a ceiling mounted fixture with a junction box behind it may reach high temps in the junction box as well.
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Yes I believe factors are involved but wouldn't one think that there is a code or specification on how to apply these factors?
Its one thing for a sticker to say "105*C supply conductors required" then leave one in the dark as to how far one needs to go to get away from the higher temp apparatus before changing to a more common wiring method at 90*C. Or does one just run 150*c conductors throughout the entire project and call it a day. Just kidding but do you get my point?
 
Steam Wells and other anomolies

Steam Wells and other anomolies

UNfortunately, I have to deal with cooking equipment all the time on this property.
Many of the countertop units we had when I got here are fully and totally prone to failure due to design flaws and very cheap construction materials. About 3 weeks ago there were 2 countertop units into the shop I had seen both possibly 4 times each in the past. They both went straight in the dumpster and some better units were ordered on the spot.
If you look at Vollrath, they have been making a mostly plastic Steam Well for many years.
They are one of the brands I don't advise. Even the drain assembly is a flanged plastic affair. Horrid.
Something like " Wells " are much better and also cost quite a bit more. Like $525.00 instead of $135.00.
Some of these units are simply not worth repairing and will continue to fail even with some repair upgrades being done.
A lot of newer generation machinery will also have issues right out of the box.
A lot of these outfits keep producing and selling junk and getting away with it because almost zero people take them to task. I have spoken to all manner of supposed Engineering departments that in truth don't know what the hell is going on and will try to con you on nonsensical engineering schemes right over the phone. " True " refirgeration is one of the all time worst in this respect with some of the worst design trends in the known universe, like attempting to cycle evaporator fans on table refrigeration with the thermostat to save a watt. Idiotic.
Not enough people are demanding accountability and a reasonable level of quality for dollars spent. This is the throw away and replacement culture that "they" always wanted in the first place.
 
StarCat said:
UNfortunately, I have to deal with cooking equipment all the time on this property.
Many of the countertop units we had when I got here are fully and totally prone to failure due to design flaws and very cheap construction materials. About 3 weeks ago there were 2 countertop units into the shop I had seen both possibly 4 times each in the past. They both went straight in the dumpster and some better units were ordered on the spot.
If you look at Vollrath, they have been making a mostly plastic Steam Well for many years.
They are one of the brands I don't advise. Even the drain assembly is a flanged plastic affair. Horrid.
Something like " Wells " are much better and also cost quite a bit more. Like $525.00 instead of $135.00.
Some of these units are simply not worth repairing and will continue to fail even with some repair upgrades being done.
A lot of newer generation machinery will also have issues right out of the box.
A lot of these outfits keep producing and selling junk and getting away with it because almost zero people take them to task. I have spoken to all manner of supposed Engineering departments that in truth don't know what the hell is going on and will try to con you on nonsensical engineering schemes right over the phone. " True " refirgeration is one of the all time worst in this respect with some of the worst design trends in the known universe, like attempting to cycle evaporator fans on table refrigeration with the thermostat to save a watt. Idiotic.
Not enough people are demanding accountability and a reasonable level of quality for dollars spent. This is the throw away and replacement culture that "they" always wanted in the first place.
Click to expand...

I think this is largely driven by customer ignorance in the restaurant industry, especially among newbies. They come in with an under-capitalized business plan or the bank won't fund the plan they really need and all they're looking at is "how much". They go out of business in a year or two and it's on to the next crop of greenhorns.
 
Cooking equipment, esp consumer even more so than commercial equipment, is notorious for poor thermal design.

Are there any "fast-on" connectors in the cookers? Those oxidize and create a poor connection and overheat.

Example: Own home, new top of line Whirlpool electric oven 45 years ago. Went thru 2 calrod oven elements in just one year.
3rd element, brazed (not soldered) 2 foot pieces of 260C rated nickel plated/Teflon insulated wire to the 'fast-on' spade lugs, far end crimped to fmc THHN
conductors.

Believe it or not, that element has lasted 44 years with no problems.
 
mopowr steve said:
Yes I believe factors are involved but wouldn't one think that there is a code or specification on how to apply these factors?
Its one thing for a sticker to say "105*C supply conductors required" then leave one in the dark as to how far one needs to go to get away from the higher temp apparatus before changing to a more common wiring method at 90*C. Or does one just run 150*c conductors throughout the entire project and call it a day. Just kidding but do you get my point?
Click to expand...

I understand where you are coming from. Experience kind of tells some of us when to expect the temp to be on the high side as well.

I have often tried to make short whips with hi temp conductor to certain HID luminaires that others have "wired through".

It has paid off for me at times with service calls later on. Luminaire goes bad or is damaged and I am asked to fix it - the high temp wire is usually still intact. When fixing a similar install by others (except they didn't whip out with hi temp) I have had to replace conductors or cut back and put in a splice box and run hi temp into the luminaire - big PITA compared to fixing one that was my install method.
 
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