Need to provide a power supply with 115V on 20 amp


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Old 12-23-17, 12:18 AM
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Need to provide a power supply with 115V on 20 amp

Good day,

My situation: I received a 1000 watt power supply from Europe that can be switched either to 250 or 115 volt. When switched to 250 it requires 10 amp and when it is on 115 it requires 20 amp.

What I need: I would prefer to have the power supply switched to 115 volt 20 amp since it used to provide power to 24 volt DC motors in a motion simulator. And since the electrical hardware will be near where I'm sitting I would prefer keeping the voltage as low as possible. Hence the reason I don't want to go with 250 volt.

My problem: I have no single-pole 120 volt 20 amp breaker installed in my breaker box that could be used for AC outlets. I only have 120 volt 15 amp single-pole breakers for AC outlets and double-pole 240 volts 20 amp breakers for the baseboard heaters. The 120 volt 15 amp lines are all 14-2 gauge so no replacement to the single-pole breakers from 15 to 20 amp could be done. I have no place left in the breaker box for a new breaker and I'm also trying to avoid running a new 12-2 cable in my walls.

A possible solution: I'm not using the baseboard heaters that are connected to one of the double-pole 20 amp breakers. Can I simply use one half of that double-pole breaker by unplugging the 12-2's white cable from the hot, plug it to a neutral stud, create a split just before the room thermostat on the wire that goes to the baseboard heaters and attached a 20 amp outlet at the end of the new branch? Or is it safer to completely remove the 20 amp double-pole breaker and replace it by a 20 amp single-pole breaker? And is it safe to create a new branch before the thermostat that would go to a new 20-amp ac outlet?

Note: My wife doesn't want me to call an electrician and spend several hundred dollars to have the job done. I must do it myself otherwise I will have to abandon this simulator project, which is no option to me.

Thank you for your help!
 
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Old 12-23-17, 06:06 AM
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Do you have blank space in your breaker panel to install another breaker?

How much current will the power supply actually consume? Most electricians use a 80% rule for a continuous load. So, you can continuously pull 20 amps from a 20 amp circuit. By the 80% rule you can get 16 amps. A 15 amp circuit can provide 12 amps continuously.
 
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Old 12-23-17, 06:26 AM
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A 1000 watt power supply will only draw 8.3 amps at 120 volts and 4.16 amps at 240 volts, at that is at full output of the power supply. Whoever told you it needs 20 amps at 120 volts is not doing basic math. If it has a standard 15 amp cord it will likely work fine on a general purpose circuit because it is nothing more then a gaming computer PSU.

To answer your other question, Yes. You could rewire the existing circuit to the unused baseboard heater and move the white wire to the neutral bar and leave black connected to the breaker. If you want to change the 2 pole breaker to a single pole breaker you will need to add a filler plate to cover the open hole in the panel. Of course you will need to install a box and receptacle in place of the heater.
 
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Old 12-23-17, 06:30 AM
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Pilot Dane,

I have no place left in the breaker box for an additional breaker. I have to use what's available. The 1000 watt power supply will feed 2 motors of 400 watt each for a total draw of 800 watt (80% at peak load).
 
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Old 12-23-17, 06:39 AM
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800 watts at 120 volts = 6.6 amps
 
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Old 12-23-17, 06:43 AM
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Tolyn,

Here are the details of the PSU that I received from Europe:

https://simukit.com/alimentations/11...24v-1000w.html

On the top-facing label it is indicated that at 110 volt the power supply will need 20 amp of current. Therefore I don't want to plug it on any circuit lower than 20 amp to avoid wire overheat and fire hazard. Thank you
 
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Old 12-23-17, 06:54 AM
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Therefore I don't want to plug it on any circuit lower than 20 amp to avoid wire overheat and fire hazard.
There will not be a fire hazard as long as the circuit you connect the PSU to has a proper circuit breaker installed. That said, the math still does not add up regardless of the label unless that PSU is VERY inefficient.

Speaking of hazards, how are you going to protect the line connections on the power supply? The screw terminals are out in the open waiting to be touched!
 
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Old 12-23-17, 07:09 AM
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Tolyn,

The psu, micro-controller logical boards and cabling are enclosed in a shell under the cockpit seat. Once the AC IN and 24v device are plugged to the psu's terminal the connectors will be covered with a non-conductive molded plastic cover in order to avoid any contact..
 
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Old 12-23-17, 07:11 AM
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Sounds good. Carry on.
 
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Old 12-23-17, 07:55 AM
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Thanks for the quick follow-up Tolyn, much appreciated. It would definitely make everything easier if I could just plug it to a regular 110v 15 amp circuit. Just to make sure to avoid any unforeseen requirements I will contact the psu company to double-check with them why are they requiring 20amp on 110V and if 20 amp is really necessary with that specific model. It might just be a question of standards in Asia/Europe since they are on 240 16amp which is twice what we use in North America for our general appliances.

Please note that the simulator will be upgraded in the next week with two new 400 motors for a total of 4 motors that will consume a total of 1600 watts at peak load. A second equivalent psu will be added to the rig. Both power supplies will be connected to the same AC outlet using a common 110v junction. Therefore the total draw of both power supplies at peak load shouldn't be more than 13 amp on 110v if these psu's are functioning normally and according to the basic law of Watt = V * Amp.

Attached is a schematic of the final configuration. The power setup illustrates the Europe 220v standards but my psu's will be switched to 110v.
 
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Old 12-23-17, 08:22 AM
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It would definitely make everything easier if I could just plug it to a regular 110v 15 amp circuit. Just to make sure to avoid any unforeseen requirements
But your house has 120 volts not 110v. Actually a good thing because that slightly lowers your amps.
 
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Old 12-23-17, 08:37 AM
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True, good catch Ray. I was using the old "110v" expression but I meant 120v ;-)
 
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Old 12-23-17, 11:37 AM
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There is a lot of "gray" area in switching power supply specifications.

I found an actual spec sheet on that Mean Well switching supply. It states 88% efficiency but that is probably an exaggerated figure. As far as connecting two of them to the same power cord.... I wouldn't.

What you actually need to do is measure the AC current draw under operating conditions. That will be the deciding factor in which way to go.

SE-1000-MEAN WELL USA Switching Power Supply
 
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Old 12-23-17, 11:39 AM
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I just talked with my people in Europe who provided me with the parts for the simulator and they confirmed that there is absolutely no risk to have a 240 volts device underneath the motion seat as long as the circuits are well enclosed and protected against external reach. This is what they do all the time in Europe since 240v is pretty common there.

In order to simplify my electrical installation I will switch the power supplies to 250v mode. This way I won't have to bring any modification to the breaker box and the baseboard heater will still be available. The only thing I will need to do is to create a split just before the thermostat on the 20amp 240v cable that runs to the baseboard. The new branch will go directly to a new 20amp 240v outlet that I'll install on the wall near the simulator. Since the heater is 1000 Watt and the two power supplies together consume 2000 Watts at peak load I will still have a free overhead of 800 Watts. The only drawback is that the power supply input are rated at less than 10 amp on 240 and the circuit will be 20 amp. That doesn't represent any risk of hazard in itself to the circuit but the breaker won't protect the device as well.

Please share your opinion if you see any risk or what not with this solution and if you have any recommendation on how I should do the installation: proper way of splitting the 240v cable, parts that I should use, etc. And by the way, the split will be done on a portion of the cable where it runs in the ceiling that is easily reachable, not in the wall.

I've drawn a schematic of the modification I'm planning to do on the actual circuit. Please see attached.
 
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Old 12-23-17, 11:43 AM
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Thank you Pete, wise suggestion. And thanks for the research and details about the psu's. What is the best way to measure the draw: a multimeter on the AC plug where the power supplies are connected? Or at the breaker box?
 
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Old 12-24-17, 12:30 PM
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I will have to abandon the idea of using a 240v line to feed the power supplies since I've just realized that these units use a L - N - FG (Live, Neutral, Ground) input. A 240v line in North America has 2 hot and no neutral so I can't connect that kind of circuit to these power supplies. It was an interesting idea since it would have provided plenty of power to the simulator but I need to find another solution. I'm back to square 1. Since the simulator will be drawing about 1600 Watt at peak load it will be limit on a 120 volt 15 amp circuit. I'm scared that this configuration could become unsafe and could damage the equipment in the long run, or even worse, make the circuit overheat and become hazardous.

What would you do if were in that situation? Please share you ideas.
 

Last edited by Justin2430; 12-24-17 at 12:54 PM.
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Old 12-24-17, 01:32 PM
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I've just realized that these units use a L - N - FG (Live, Neutral, Ground) input. A 240v line in North America has 2 hot and no neutral
That does not matter with switching power supplies in most cases. The only possible safety issue is if the power supply has built in power switch and that switch only cuts one pole (line). As long is both poles are switches off, there are no safety issue.
 
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Old 12-24-17, 01:43 PM
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Lambition, do you mean that I could plug one of the 240v circuit's hot to the neutral and the other to the live?

See attached picture
 
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Old 12-24-17, 02:27 PM
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It doesn't matter if line to neutral is 240 volts, or line to line is 240 volts, either way is it 240 volts.

Connect one wire to the L terminal and the other to the N terminal. It doesn't matter which one goes where. Ground gets connect to the FG terminal.

Just make sure you have the switch set to 240 volts.
 
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Old 12-24-17, 02:33 PM
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do you mean that I could plug one of the 240v circuit's hot to the neutral and the other to the live?
Yes. Most AC devices don't really care about neutral or line. All that matters is voltage between 2 wires.
Only case neutral matters is when the neutral is also being used as ground or reference voltage of output in some way.
 

Last edited by lambition; 12-24-17 at 05:30 PM.
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Old 12-24-17, 04:24 PM
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Thanks Tolyn and Lambition. Your help is more than appreciated. I'm glad I asked since what you confirmed will make a major difference in the efficiency of my installation. I know very few about that type of psu and its connectivity specifics. And I don't know a lot about the specifics of the double-pole 240v circuit. I've always worked with 120v with the simple hot and neutral 1 phase circuit and I feared that connecting a live 120 volt to a neutral stud would make the device go in flame. I'm glad it can work.

Happy Holidays!!!
 
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Old 12-26-17, 08:25 AM
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Lambition,

Before trying the option of plugging the psu's to 240v I will do a first test on a regular 120v ac outlet to see if the circuit can take the load. I will start with 3 motors. The total peak load of the 3 motors will be 1200 watts. The circuit should take it. The only thing that bugs me is the 20amp specs written on the psu sticker but logically they should need that much power. For 1200 watt on 120 v the psu should not need more than 12-13 amp.

I already tried one psu with on 1 motor on 120 and it ran normally.

Note: As an extra measure of safety I will plug each two psu's in a power bar that has a surge protection and it's the power bar that will connect to the 120 v ac outlet.

If the circuit is starting to overheat because of the electricity demand how will I know before a damage is done? Can I just touch the cable to see if a temp difference occurs? I have a multi-meter. Can I just test the circuit during load time and where is the best place on the circuit that I should install my multi-meter to get the most accurate reading?

Thanks
 
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Old 12-26-17, 12:28 PM
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A surge suppressor will help protect anything plugged into it from surges coming down the power line. The suppressor does not provide protection in the other direction so plugging your device into a surge suppressor does not protect the house from overloads or other problems unless your surge suppressor has it's own circuit breaker.

Look at your multimeter and see how much current it can check. Most can handle 10 or 15 amps. You could hook up the meter and only power one motor and check the draw.
 
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Old 12-26-17, 12:57 PM
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As long as your 120V circuit wired with correct size wire and breaker, it will not cause any harm to the wiring. Breaker will trip when the circuit is overloaded.
Most properly made surge protectors also has built in breaker that will trip when it is overloaded. This built is breaker is sized to the maximum load surge protector/power strip can handle. However, most are only rated 10A.

You can connect multimeter is series with the circuit anywhere between outlet and power supply. However, most low end multimeters cannot take continuous 10A or higher loads. They are designed to handle high current for something like 10 sec (it will say on the meter) and often they are non-fused. Overloading will burn the shunt and kill the meter. High end multimeters can handle continues high loads, but these meters are expensive and many are still only rated 10A.

I'd recommend a clamp meter for high loads like that.
 
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Old 12-26-17, 03:19 PM
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Thanks Lambition and Pilot Dane. I verified my old meter and it won't be of any use since it has a limit of 200mA (0.2 amp) in DC. No option for 15 amp metering in AC. It's a pocket size model that is more oriented for small electronic projects but I was sure it had that function... no luck.

I've just asked my parts provider in Europe to test the amp draw of his simulator and come back to me with the numbers. We have the same model. These numbers will be the definitive answer as to what type of circuit I will choose: 120v 15 amp or 240v 20 amp.
 
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Old 01-04-18, 09:46 PM
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Hi all,

I performed several tests with my three 400w-motor motion base plugged on a regular 15amp 120v line and so far, no problem. The breaker didn't trip. More over the test were performed on a line already used by a high-end computer and a 55in LED TV. However I shut down the lights in the room to spare voltage draw on the main. When lights are on I could see them dimming when the motors were drawing more power under heavy load and surge motions. I didn't install the whole 100-pound simulator cockpit on the motion base yet so the motors are not fully exploited in the moment. I'm planning to dedicate a 15amp line only for the simulator and I think that it could be enough to satisfy the power demand.

I'd like to protect the simulator equipment (and the line/breaker) against any power variation and I wish to have your opinion on the best power regulation that I can get at a reasonable price (under 200$). I found this solution. Do you think that this can do the job? Would you recommend something else. Unfortunately this device doesn't have a digital panel with the details of the power consumption (volt/amp/etc).

1800W 120V Power Conditioner with Automatic Voltage Regulation

https://www.tripplite.com/1800w-120v...utlets~LC1800/

Thank you
 
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Old 01-04-18, 10:41 PM
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Reading your post and I have to agree with the other guys. These power supplies can't possibly need 20 A at 120 V. They output 24VDC @ 42 A. That's only 1008 watts, plus some overhead for the fan, etc. if that's even an accurate rating. But if you really want to see what they draw and gain some peace of mind about your install, buy yourself a Kill A Watt power meter. These plug in to standard US outlets and accept an appliance plug on the other end. You can easily monitor amp draw without exposing yourself to a live circuit. It just plugs in between the outlet and appliance. Super simple. I have one in addition to a half dozen various multimeters and it's very handy. I used it a month ago to help my neighbor who couldn't figure out why his Christmas lights kept tripping the breaker (he was drawing 18.5 A on a 15 A circuit).

Finally, don't believe it needs 20A just because the label says so. The part of the product label that concerns me most is the part that says MADE IN CHINA. I've read many a Chinese written manual and they are CHOCK FULL of typos and incorrect data. Just use the $20 meter and accurately assess the current draw yourself.
 
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Old 01-04-18, 11:04 PM
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Tks Rickalders. I agree with you all that my very first step should have been to get a decent amp/volt meter before getting into too much dwelling. I will definitely do so. Is that the model you were thinking of? It has volt and amp metering which is exactly what I need. I'll try to find it in a local home hardware.

https://www.amazon.ca/P3-P3IP4400-El.../dp/B00009MDBU
 
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Old 01-06-18, 08:16 AM
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I just ordered this newer model of the Kill A Watt P3. It has an internal battery that keeps the history of the power consumption and a 0.2% reading precision. The unit should arrive this Monday. Will keep you posted with the results.

https://www.amazon.ca/dp/B000RGF29Q/...709270_TE_item
 
 

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