Pizza Oven 240 vs 208

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110.4 Voltages. Throughout this code, the voltage considered shall be that at which the circuit operates. The voltage rating of electrical equipment shall not be less than the "nominal" voltage of a circuit which it is connected.

I consider the word "NOMINAL" in 110.4 to mean in engineering terms:

"Real versus nominal value in engineering - a value that is used as the name for an actual value which is close but not exactly the same."

Now, taking your approach, let me ask you how many 115 volt rated appliances have you installed on 120 volt sources which actually operate at or near 130 volts? "SHALL NOT BE LESS THAN "NOMINAL VOLTAGE"". I had a code instructor years ago that always preached " knowing the code is important, but knowing why it is code is more important". His name was Mike Holt.
 
charlietuna said:
I don't think the motor,nor the elements will know the difference in a pizza oven while operating at a higher voltage and lower current draw! MY$.02.
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Sorry, Charlie. :grin: Within a certain range, a motor will use less current on a higher voltage, but the current of the heating elements will rise with the voltage.

My shop's service was a delta, so i took that lighting circuit and put it on the highleg.
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You mean they're connected from the high leg to the neutral? That's supposed to be a big no-no for the transformers.
 
True the motor will draw less current since it is doing the same amount of work.

The heating elements will produce more heat, but the thermostat will control the oven's setpoint.

"Connecting the high leg to the neutral" --now i never said that! That will cause you a major problem!
 
charlietuna said:
The heating elements will produce more heat, but the thermostat will control the oven's setpoint.
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Now again your assuming a 'standard oven' which I don't belive it is. There is also no way for us to know if the unit can tolerate the elements running at a higher temp.

110.4 Voltages. Throughout this code, the voltage considered shall be that at which the circuit operates. The voltage rating of electrical equipment shall not be less than the "nominal" voltage of a circuit which it is connected.

I consider the word "NOMINAL" in 110.4 to mean in engineering terms:

"Real versus nominal value in engineering - a value that is used as the name for an actual value which is close but not exactly the same."
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Right, the 'Nominal voltage' of the building is 240.

The nominal voltage rating of the oven is 208.


To connect the 208 listed equipment to a 240 nominal source is in fact a violation of 110.4




Now, taking your approach, let me ask you how many 115 volt rated appliances have you installed on 120 volt sources which actually operate at or near 130 volts?
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Two problems here with your thoughts.

A 120 nominal system is still a 120 nominal system when operating at 130 volts.

The 115 volt rated motor is designed to run on a 120 volt nominal system.

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"I had a code instructor years ago that always preached " knowing the code is important, but knowing why it is code is more important". His name was Mike Holt.
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I am missing your point, the 'why' of 110.4 is clear, do not connect equipment that is listed for use at a certain voltage to a voltage system that is higher.
 
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Bob,
What is the source of voltage regulation chart standard you posted?

I find article 110.4 very clear and have posted the meaning of the word "NOMINAL" in the eyes of engineers.

It's been common practice for years to use 208 volt motors on 240 volt circuits and vice-versa. Of course you must adjust the overloads for the voltage.

i disagree with you!
 
charlietuna said:
Bob,
What is the source of voltage regulation chart standard you posted?

I find article 110.4 very clear and have posted the meaning of the word "NOMINAL" in the eyes of engineers.

It's been common practice for years to use 208 volt motors on 240 volt circuits and vice-versa. Of course you must adjust the overloads for the voltage.

i disagree with you!
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Dual voltage rated motors maybe, but not what you describe is ok. The other thing to consider about this is the thermostat will not operate as it should, it will most likely run at a lower temp than the setting is showing.
 
Hawaiian "brudder",
Please explain how the thermostat is effected by higher voltage?? It turns "on" and "off" the voltage to the element at the customer's chosen setpoint. True the elements will get hot faster, but thats about all.

The area of our trade where this is an issue is restaurant equipment. In my apprenticship years i worked for a contractor who represented some major equipment distributors -- we never had a problem with this issue! Equipment would come in for a new chain store with all kinds of voltages on their nameplates -- there was no shipping it back! And we serviced these same chain restaurants. In the past ten years we have had issues with copy machines not operating correctly on wrong voltage and we would install buck/boost transformers--and to tell you the truth, i always questioned if this was the true cause of the problem! And another area is in the printing industry, where many items are rated at 200 volts, not 208, but function fine on 240 volts.
 
charlietuna said:
Hawaiian "brudder",
Please explain how the thermostat is effected by higher voltage?? It turns "on" and "off" the voltage to the element at the customer's chosen setpoint. True the elements will get hot faster, but thats about all.

The area of our trade where this is an issue is restaurant equipment. In my apprenticship years i worked for a contractor who represented some major equipment distributors -- we never had a problem with this issue! Equipment would come in for a new chain store with all kinds of voltages on their nameplates -- there was no shipping it back! And we serviced these same chain restaurants. In the past ten years we have had issues with copy machines not operating correctly on wrong voltage and we would install buck/boost transformers--and to tell you the truth, i always questioned if this was the true cause of the problem! And another area is in the printing industry, where many items are rated at 200 volts, not 208, but function fine on 240 volts.
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Not sure exactly how to explain it except I have witnessed it as well where the higher voltage messed up the temperature guage for the oven, and it read lower on the digital readout than the actual temperature that the oven got to as per a second freestanding thermostat placed into the oven confirmed. Once the voltage was bucked back to where it was supposed to be (208) everything worked fine and the elements haven't had to be changed since. The kitchen manager told me that before I converted the voltage the elements had to get replaced about every three months.
 
Maybe the original adjustment of the T-stat maintained the average temperature using the expected heat rise time and loss time.

A higher wattage makes for a faster rise time, but doesn't affect the loss time, so maybe the average temperature ends up higher.
 
We have done quite a few commercial kitchens and there is a lot of kitchen equipment that the nameplate will only have 208v on it. Which I was always under the impression was still nominal for 240v. Until we started seeing equipment with tags that say "NOT RATED FOR USE ON 240V SYSTEM".

So if the nameplate isn't dual - 208 / 240 it gets a transformer in our installs.
 
I'm sorry if I missed this in the other posts but are we talking about an electronic "thermostat" or a plain-old on/off type?
 
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