capacity of an electrical circuit

...yes. Most residential duplex (wall outlets) recpticles are circuit-breakered or fused for 20A, thus ANY combination of two of the freezers exceeds 20A...adding the third freezer is certainly WAY too much, and the circuit-breaker is "properly" tripping.

...you need to either (A) run two more separate electrical lines each with its own circuit-breaker (ideal); or, at the very least (B) run one more sepate electical line with its own circuit-breaker (not really enough).

...maybe there's some demand-timing "device" available to ensure that only ONE freezer can be "on" and a time, and when the first freezer is done running will automatically "switch" over the next (priority) freezer needing to be running?

Hello sallison,

Your current 20A circuit is not design to supply that heavy load, the breaker trips because of high currents(amperes).

you have two solution

1. Add new circuit 30A breaker to supply only two large freezer

2. change the whole circuit with higher amperage probably 50A

NO NO NO

If you increase the beraker to 30 or50A you will also need to change the outlets and cord and plug on each freezer to match.

Your best bet is to run a 20A ckt to each unit you only need to run a 12/3 rx cable to get 2 more 20A ckts this will also pervent loosing all 3 units if a breaker trips melting all your goods insted of only loosing one unit

Whoa up there Lighting up USA,

The 30A/240V circuit needs to be split to 3 15A/115V circuits, is the reason I suggested using a distribution panel. I've found the work simpler this way.

No changes to existing power cords required...

That was for AUTOZAM's comment.

Depending on his location to the main panel a sub panel might work out better ie: future loads?

Good thing .Cable not heated up and burnt.

Please connect each freezer in seperate outlet.do not club all the freezers in one outlet.

Do you know what your local electrical code requires for such an application? Where I'm at, it would be required to have a "home-run" - (dedicated line) - for each of those freezers.

One solution would be to put in a larger circuit breaker, assuming that the wire is the appropriate gauge to accomodate such a load.

This is a link with a chart telling you what each gauge can handle. But as Sparky said, the initial draw is much higher, and needs to be factored in.

http://www.powerstream.com/Wire_Size.htm

It is doubtful that the wire supplying power to these freezers is even large enough, probably 10-12 gauge, but there may be another possibility...

This is a longshot. Are these freezers stand-alone units? What I mean is to find out if they're controlled by some sort of PLC. If so, you may be able to keep them from "starting" at the same time by programming the PLC to turn them on one at a time. This would help keep the load under the maximum rating.

I'm not sure about this, but starting and stopping the freezer at certain times are just inefficient since it consumes a lot of current to start the freezer. At the end of the month you will be surprise about your bill.

My proposal would assume that it would be programmed to turn on and off as needed via input from a thermostat.

Don't understand the chart . Every chart I've seen and in the code book it calls for 14 ga for 15 amps , 12 ga wire for 20 amps and 10 ga wire for 30 amps . Being as that it's in the electrical code book I wouldn't say that it's just a guideline or rule of thumb . Can see going up in wire size when it's derated for a long run , but certainly not smaller than the code . The circuit breaker is sized to protect the wire , and the wire is selected to handle the load . ---- Inefficient to start and stop the freezers ?? The compressors don't run all the time . They switch on as required to maintain the temp desired . They draw max current on starting and once running , the current drops to something below full load current . Should not really change much on total current usage if you controled them so no two compressor motors started at the same instant . One compressor starts , and perhaps 4 or 5 seconds the second compressor starts after the first compressor current draw drops off . Doing it this way would probably let you run two freezers , but unlikely three . One thing for sure , is if you decide to just put in a larger breaker without large enough wire , you may build a toaster . ---- efficiency ???? Poor door gaskets , opening and closing the door unecessarily , or not keeping much in one all run up the electric bill .

The breaker you have is just right for the wire gauge. Increasing the breaker's Amps might cause you problem, if not the moment you change it, it might occur in the future. Spending time to run another line will save you from disaster.

sallison,

No, you have to run another circuit.

I would run one three wire cable @ the gage required in your area to at least a 30A satellite distribution panel at the freezer location. In this dist panel have three 15A breakers to provide one separate 15A circuit to each freezer. The cost difference of a 50A is significant over a 30A, the 30A dist panel is sufficient for the service you described but do check local codes.

Electricity is controlled smoke...

You really should run 3 circuits (2 more) and therefore have a separate breaker for each freezer. Why? you may ask, well I assume that what is in the freezers must stay cold and if a fault occurs and blows the fuse, at least the loss of the contents will then confine itself to one freezer.

Also, as someone mentioned, the starting current of any two freezers on the same circuit, occurring exactly together, could still occasionally blow a fuse......even though the current draw is seemingly less than the fuse in question.....

Running two extra circuits will only cost marginally more than running one and you must run at least one I feel.....

Battery driven Freezer monitors with alarms are also a good idea too......

13Amp + 15.7Amp + 12.3Amps equals 41Amps. There you have it. Too much for the circuit. I don't know of a device that always keeps two of the freezers shut off, though their may be one. Doesn't seem very straightforward and simple a solution to me. Also typical house ciricuits are usually 15 amps in most rooms, and only 20 in the kitchen. The breaker rating is on the breaker in the box.

As well if you have repeatedly tripped a breaker, it may have become pitted and need to be replaced.

FIrst you have check the total power requierment i.e each freeze -watts. Normaly you will abel to see on on freez name plate. The mathematical sum of all three freez watt ( powwr ) multiply by 1.25 time is total power requierment . That means if sum of all three freez watt comes to 1500 watt, The actual power requierment will be 1500 x 1,25 = 1875 watts divide by 115 volt = 16.30 Amp. That means you need 20 Amp MCB. You can calculate your own way & decide AMP rating of MCB

Secondly you have to check MCB you must use "B " curve for freez load , so ensure that you installe 20 AMP MCB with mark as ' C " Curve if it B curve you have replace with 20 -C.

There is a way you can probably make it all work, but you'll need additional controls to do it.

First, A freezer only needs to run to make up for heat gained from the outside or to cool contents initially placed into it. This means that on the average a normal freezer probably runs much less than 25% of the time.

Second, a 20 Amp circuit is capable of handling one 16 amp load continuosly. Since your largest freezer is 15.7 amps, the circuit is adequate for any 'ONE' of your freezers at a time.

Third, construct a control circuit that only lets one freezer run at a time. Feed 3 contactors from the 115 VAC, 20 Amp source. Connect an outlet for each freezer to the load side of one of the contactors. Put a current sensor in series with each of the freezer circuits that prevents the other two from closing if curent is flowing in the third circuit. You would need a threshold setting, say 1-2 amps, to allow for normal freezer idle current without tripping the sensing circuit.

Operation: whatever freezer turned on first would lock out the other two freezers. When the first freezer cooled down to setpoint temperature and shut off it would stop drawing current and enable all three freezer circuits. At this point if either of the other two freezers required a cooling cycle it would turn that freezer on and lock out the other two circuits until it had completed its cooling cycle. This sharing of the single circuit could continue indefinitely, and unless you loaded all three freezers with lots of warm items at the same time, it wouldn't cause any problems with any of the freezers or their contents.

Such a control system would work, but might be more complex than running 2 extra lines and installing 2 extra breakers. Also, it would make sure a qualified electrician is there to ensure the intermittent load does not exceed the panel rating.

If there was no more room on the panel, then such a control box would enable the freezers to run at their allotted time one after the other all on one circuit breaker. I don't know where you would find such a unit though. It would be pretty simple...just a switch that makes one of three outlets "live" at a time. I expect it would look like a power bar. Anybody know where to find one?

On second thought, never mind, sure as heck some well meaning soul would replace the switching unit with a power bar. ButI knew I had run across something similar a lifetime ago, and it was legal at the time. It would likely not be legal in commercial installations, or in other countries with their own codes.

Here is the relevant section in the Canadian Electrical Code, admittedly a couple of years out of date. Its on "Appliances Exceeding 1500Watts", which these freezers do. The phrasing suggests cook tops or space heaters, but the freezers ARE an appliance, so this must apply to them as well.

26-748 Appliances exceeding 500 W.

(1) Every electrial heating and cooking appliance rated at more than 1500 W shall be supplied from a branch circuit used solely for one appliance except that more than one appliance may be connected to a sing-branch circuit providing that the following is used.

(a) A multiple throw manualy-operated device that will permit only one such appliance to be energized at one time; or

(b) If the appliance has more than one individual heating element each controlled by a switch, no main switch need be provided.

The relevant part is part (a) above...you could have each item switched one after the other, but it says it has to be a "manual" switch. So the guy running the freezer will need to power down one unit before powering up the next, and you can't use automatic equipment for that. Or, you are allowed to unplug one freezer and then plug in a second in the same receptacle, providing you turn off the freezer first. (part b)

Notwithstanding that, in commercial installations, the standards are much tighter, and will demand that three freezers will have 3 power supplies going to three breakers. Then it becomes cheaper and more effective to just install the proper wires and breakers, and more importantly, nobody will be tempted to automate, bypass, or generally do something stupid to what should be a fairly straightforward system.

Thank you JRaef and Sparkstation for your excellent comments!

Sallison, I hope that you will Please take these comments to heart and do it the RIGHT way.

3 freezers, 3 circuits! Anything else would be a code violation and also violates COMMON SENSE!

The small amount of money and time expended is a mere pittance when weighed against the cost of replacing your home or business and its contents due to a preventable Fire.

Hello JRaef

I have given you a Good Mark for your Post.

Cheers.

Kind Regards....

3 20A breakers? Plus the cost wire 3x? That's quite a tidy sum.

Why not one 30A or 50A circuit to a sub panel and then split the 240V into 3 115V 15A or 20A circuits? He may get another large appliance someday but if not this way is cost effective.

Hi snygolfgs,

You go ahead no wrong done being single minded or unmovable on this subject, you may be correct a thousand times and not get even a smile but do it wrong and you'll never be forgotten.

I tend to look to cost effectiveness while maintaining and classifying safety as paramount.

I use the sub-panel concept in these type situations where is a heavy current draw for a few safety reasons:

If a trouble occurs with a freezer; an alarm may sound or a person may run to the freezers first then if an electrical trouble; fire etc., be able to secure the energy on location. Grabbing a smoking power cord is bad news in comparison.

If you were working in the freezer area and need cycle power on then off for what ever reason a sub-panel will save steps.

Normally I use minimum 100 amp sub-panels because it just makes sense.

You're welcome,

John

Hi John,

Sorry I haven't replied before now. I only look at this thing for a few minutes each night.

My only point was that a seperate circuit is required for each unit. How it's done doesn't really matter as long as it conforms to all local and national codes and an inspector would be happy looking at it.

Have a good evening.

Jeff

Get a device that measures when power/current is flowing. on the detected signal output, use that to disable the power on the other 2 appliances.

Once number 1 gets to setpoint, number 2 is activated, then number 3, then 1 again.

Or pay someone to run a new circuit, get 3PH installed and run it to 3 points at the rear of each unit.

You should have 3 circuits for the three freezers.

Some people have used timers to control the load without rewiring.

I would run two new wires here.TOO MANY WATTS

OK. The sum of all the amps is 41.0 amps continuous, and any two continuous loads add up to more than 20A. So the 20A breaker is doing its job correctly, which is to protect the cabling between it and the downstream socket outlet(s) from overheating and the consequent risk of causing a fire. Do not under any circumstances replace the breaker with one of a higher current rating without upgrading the cabling, as that will leave the existing downstream cabling unprotected and a fire will surely follow.

Is there scope to reduce the quantity of food/drink stored so as to reduce the number of operational freezers needed, and with cascading one or two freezers out free-up some space in the building?

In addition to the good advice in the above posts, another option would be to separate the freezers by plugging them onto three separate pre-existing circuits, if present electrical distribution will allow this to take place easily.

If this is not possible, then from the nature of the wording in the posting, it would seem an appropriate course of action would be to consult a properly-qualified local electrical installer at the earliest opportunity and have additional circuit(s), for two of the freezers, to be run-in, tested, and certified.

Keep the installation test certificate filed in a safe place as it can prove a valuable valuable when the building changes ownership (in the UK, Surveyors look for these things when advising the prospective purchaser).

Another reason (besides electrical codes and safety) to go with 3 20amp circuits, one for each freezer; If down the line you need to service/repair a freezer you will have to turn the breaker off to service it. If they are on seperate circuits you will not have to take down power for all three freezers just to service one. I guess you could just 'unplug' the freezer you needed to service but that might entail moving the freezer to get at the service disconnect which may be troublesome depending on its weight and size.

There are often many ways to accomplish a task, often doing it the 'right' (at times more expensive, initially) way in the begining can save you alot of headaches (and money) in the future, not mention the safety concerns.

By right way I suppose you meant have a disconnect within easy reach?