changing breaker box

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  #1  
Old 02-22-11, 03:10 PM
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changing breaker box

I have a concession trailer. The main panel(Sq D) has a 50amp main. I am out of space for additional breakers. Will a fryer rated at 208v 3phase be able to run off this panel?
 
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Old 02-22-11, 03:52 PM
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We will need more Info. What is the panel- 1ph or 3 ph? How many amps does the fryer use? Most concession trailers only have a nema 14-50 plug. Also, most fairgrounds (in my area, anyway) are too cheap to purchase three phase, or even equipment rated for outdoor use. It is usually a GE 100a main lug panel fused at 400A powering 10-12 trailers. Dont trip or you will pull the breaker out of the panel.
 
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Old 02-22-11, 03:55 PM
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Welcome to the forums!!!!!!!
 
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Old 02-22-11, 04:23 PM
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Originally Posted by onthego View Post
I have a concession trailer. The main panel(Sq D) has a 50amp main. I am out of space for additional breakers. Will a fryer rated at 208v 3phase be able to run off this panel?
Most likely it will not work as-is. Some fryers can be reconfigured to operate on single-phase power, but your 50A connection may be a limitation. Do you have the electrical specifications of the fryer (amps or watts)? Do you have a make/model and or wiring diagram for the fryer? What other types of items are powered in your trailer from the other breakers?
 
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Old 02-22-11, 06:20 PM
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Here is what is powered now in the trailer. small fryer 3000watts, heat lamp, h2o tank, 3 flourescent lights, refridgerator, beverage cooler. The new fryer is 47.5amps per leg. Most events I have been at , except for a few, only have a max of 50amp service per trailer.
 
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Old 02-22-11, 06:24 PM
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Also there is a roof top A/C unit. But that I can disconnect if power is an issue.
 
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Old 02-22-11, 07:27 PM
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The new fryer is 47.5amps per leg.
Your fryer needs a minimum 60 amp 3 phase circuit. You cannot connect it to your existing panel successfully even if it is a 3 phase panel because you are limited to 50 amps. I'd suggest checking the loads you now have and looking for a much smaller fryer.
 
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Old 02-22-11, 07:29 PM
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No. The fryer needs a 60a MINIMUM cirbreak, and you also need to power everything else. The smallest panel I would use is 125A. you're better off buying a gas fryer.
 
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Old 02-22-11, 07:35 PM
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If that fryer indeed pulls 47.5A (which on 3 phase is 30,000 watts), it would require a 60A circuit all by itself, because you have to allow for derating. Absolutely no way to run that if you only have a 50A feed for everything. A 3 phase unit will have 3 separate 10,000W ([email protected]) heating elements. If it is 1 or 3 phase convertible, it will require 3 times the current at 1 phase (144A - would require 3 separate 60A double pole breakers, one for each element). If you need a fryer that big, you would be better off getting one that runs on propane, and saddling a pair of 40lb propane tanks on your hitch..
 
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Old 02-23-11, 04:53 AM
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Thanks everyone for the input. I didn't think this would work. I will be looking toward a smaller fryer like the one I already have. This is a great forum for advice. Very helpful.
 
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Old 02-23-11, 04:56 AM
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I am still going to be short on space in the existing panel since all the breaker slots have been used. Some of the single breakers have been replaced with doubles. Can I upgrade the panel to a 100amp but only put in a 50amp main? I will just need the extra breaker space.
 
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Old 02-23-11, 08:26 AM
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Can I upgrade the panel to a 100amp but only put in a 50amp main?
Yes.

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Old 02-23-11, 09:57 AM
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Now as I understand electrical. The box main will be rated at 50amps. Is that assuming I will not pull more than 50amps at any one time. Even thou I have something along the lines of 85amps worth of breakers?
 
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Old 02-23-11, 10:20 AM
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Yes that is true for most "general-purpose" installations, but in your case you should probably do the actual calculations. The reason is that in a house, for example, you only use one or two rooms at a time so most of your breakers are "unused" at any given time. However, in your concession trailer you know that pretty much everything will be turned on at the same when you are open for business.

You should figure out everything that will be powered on during business and add up the power (watts) for all those items then size the electrical service accordingly. You are also restricted by the fact that fair ground hookups are usually no higher than 50A so you have to work within that limit.
 
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Old 02-23-11, 10:20 AM
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Originally Posted by onthego View Post
Now as I understand electrical. The box main will be rated at 50amps. Is that assuming I will not pull more than 50amps at any one time. Even thou I have something along the lines of 85amps worth of breakers?
This assumes all of the breakers will not be at full loads. It assumes that at any time the total load on all the breakers will not exceed 50a. The 50 amp breaker does not prevent more then 50a being drawn but if it is it will trip preventing the condition from continuing.
 
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