I expect a large fridge to draw around 5 amps, but my clamp transformer (on one wire of a broken-out extension cord of course) and Fluke together say 830ma when the thing is running. Does that seem wrong? It measures the toaster oven at 9.1A and the fridge light at 300ma.
Are sure that is not just a fan running without the compressor running? It has to be more when the compressor runs.
Mikek
That sounds about right. A refrigerator maintains a low temperature, but ta kes a long time to pull the contents down from room temperature. The compre ssor is tiny, inside the housing It is spring mounted to reduce the noise, and to surround the motor with refrigerant. If it drew 9.1A, that would be over a Kilowatt that would need to be dissipated, along with the interior h eat.
We measured a new fridge at the store, had to talk the manager into it but I built a box with a cord and outlet and a wire looped outside for a clamp on ammeter.
We got a peak of like 9 amps or so to start but then it went be;ow one amp.
However if the thing has not been in service the condenser is not pressuriz ed which does make the compressor draw more. We didn't want to hang around all day so we took the data and went on to other things. This was for a sol ar powered camper made out of a box truck.
The trend now is for a smaller refrigeration system that runs longer. The p eak at startup is one issue but there are so many others. Manufacturing cos ts, weight/freight. It all needs to be considered when you make decisions l ike that in design.
There are drawbacks. I would bet real money that if you put a new and old f
ew one would not. But how many people are going to do that ?
So you might have 80 watts for 6 hours but with an old one you would have 1
60 watts for 3 hours. The lower drain means less loss of power in the house wiring, and not contributing as much to peak demand.Thing is, after the startup surge, take and run the thing for a couple hour s with the doors open. Then you get a worst case scenario value for its cur rent drain.
Thanks to all. This is good, so I can put some other loads on the fridge outlet.
Maybe, maybe not.
While typical refrigerators these days pull one amp (or less...) while running, the "frost free" ones use a hell of a lot more during the defrost cycle.
I've measured _500_ watts (4 amps) on mine.
A meeting hall I work with had a problem where the circuit breaker feeding the overhead lights would overload and open up, plunging the room into darkness.
Which made no sense. Yes, I re-measured the load and swapped breakers...
On checking further, I found that they had added an outlet which was slaved off the lighting circuit [a] and was being used for a refrigerator.
It took some head scratching before I realized that when the lights were on at the same time the refrigerator went into defrost mode, the power draw exceeded the breaker rating.
Since the place was rarely used, just about all the time the defroster kicked in the lights were off, so these blackouts were few and far between...
[a] installed by a professional and licensed electrician who should have known that Code does NOT like appliance outlets on lighting circuits for exactly this reason.-- _____________________________________________________ Knowledge may be power, but communications is the key dannyb@panix.com [to foil spammers, my address has been double rot-13 encoded]
Make and model of the fridge? 117VAC or 240VAC? I can possibly lookup the expected current drain online and do a sanity check. I found a few charts that claim a full size refrigerator/freezer should draw about 700 watts. 5A sounds about right: 117VAC * 5A = 585 VA No clue on the PF (power factor) so I'll use VA instead of watts.
If you're seeing only 0.83A, then you're looking at the current drawn by a fan or light bulb in the fridge, not the compressor. Try lowering the temperature setting of the thermostat temporarily to force the compressor to start.
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Frigidaire FFHT1621TS1
Tthat 800ma is when it's making noise. It's less than 10ma the rest of the time. The other loads are toaster and microwave so they draw zero most of the time.
The most unfortunate thing is that all the outlets in the kitchen seem to be on one breaker. I say so because there is a 3 volt drop on any outlet when the toaster oven draws 9 amps. In another room it drops
100mv or less.
That might be a few times a day but my other loads are used even less often. The total is still under 15 amps which is what motivated me to measure it.
Newer ones seem to draw less on auto defrost. I think some older ones may draw a bunch, like 10 amps or more.
Greg
a fan or light bulb in the fridge, not the compressor.
No, I am sure of what I said, that was considered at the time.
But if the compressor is not pumping into a loaded condenser the power drai
Go look, you'll see I am right. It just so happens I have recent experience with this. Not many people last year went into a store and convinced the m anager to allow connecting an ammeter to one of their new refrigerators. I did.
Besides the NEC violation, the other reason not to share the fridge circuit is when/if the toaster/mixer/whatever trips it, and you do not notice, you get was-frozen food.
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In general, the best means of deciding how much current a device takes is a peak-holding watt/hour meter. Various devices may be purchased at your local Big-Box, Amazon and any number of other outlets.\
Such devices are also good for discovering real or pending problems with appliances and any number of other items around the house.
Why speculate when good data is readily available?
Peter Wieck Melrose Park, PA
Because this is Usenet. The standard rules of engagement are to take something simple, blow it all out of proportion, then continue to beat it like a dead horse with wild speculation.
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I'd have a little concern about that 3v drop. It could be just a long run of wire, (I doubt it) or a poor connection somewhere between, starting at the box and going to the outlet. Warning I once connected several freezers to an outlet, in an outdoor porch. It was fine for years and then one day a got a burning smell. Tried and tried to sniff it out, but it went a way. A couple days later I smelled it again. I traced behind a TV, I grabbed the TV plug and it was very hot. I moved everything out, removed a panel from the wall. Upon inspection the the outlet crumbled to pieces. The wire from the Circuit breaker box terminated at the outlet, then another wire was connected to the box that went to the outdoor outlet. A poor connection to the box, heated up every time the freezers ran. I was lucky it didn't start a fire. I installed 220v to a sub box and divided that for my freezers after that.
Mikek
Yeah, thanks, but I realize that. It's the landlord's fault if the building burns. I have my own insurance. His might be cancelled.
a) If the landlord provides wiring that is/was to-code when installed. b) If the code states that a refrigerator should be on a dedicated circuit. c) If the tenant attempts to go around the original and proper installation and/or add additional load than just the refrigerator.
It is unlikely the landlord will get dinged 'if the building burns' - as th e lawyers will go through the first-cause (you) first.
Line drop: is it 3 volts under load? Is it 3 volts in general? What gauge i s the wire, and how long is the run? And are there any splices along that r un? As an example, we have a 12-gauge, 20 A dedicated circuit to our refrig erator that is about 75' in developed length, no splices. Just for giggles, we have 118 V at the panel, line-to-ground, and 117 V at the receptacle, u nloaded. And within the limits of measurement error anyway.
Peter Wieck Melrose Park, PA
Hope you're not sleeping if a fire starts! My problem really shook me, because of the way the wood was scorched inside the wall. If we had a hot night when the freezers had to run, a fire could have happened. It's a 45 year old house, hmm, it was only 20 years old when I moved in. Mikek
With a 10 Meg ohm DVM, That doesn't sound right. 150ft of #12 wire is 0.2382 ohms, add 0.1 ohms for the 4 connections and you have 0.3382 ohms, you would need 4.2 amps to drop 1 Volt. Are sure there is nothing else on that line?
Couple clarifications, What do you mean by developed? and line-to-ground? is it a two wire system? Line to ground, line to neutral should not be different, But... Mikek
Developed length: The total amount of wire in the run. Not the direct distance between the panel and the receptacle, which is less than 60 feet.
Standard Hot/Neutral/Ground 12/2 Romex. And, as the Neutral and the Ground are bonded to the same buss-bar, the voltages are the same.
Consider a measuring device (voltmeter) - and it has a margin of error. Consider that at the panel, it is measuring at the bottom of the 118 V level, and at the receptacle, at the top of the 117 V level. That is what I mean by measurement error.
Peter Wieck Melrose Park, PA
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