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Does anybody use a power meter?


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I have. Power strip with 4, sometimes 5, laptops plugged into it, plus a couple monitors, speakers, external hard drives. I’d like to know what its maximum power draw is. If it’s close to the limits of the wiring, I will reorganize things. Does anyone do this, have recommendations?

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Most power strips have a breaker built into them and are usually 15 amp. If it doesn't, get one that does. That totals out to 1725 watts available. If you want to add up each appliance the wattage or Volt Amps is printed on the label/power supply.

Your wall outlet is breaker-ed at 20 amps. This is the maximum current draw on all the outlets wired to that breaker. Assuming that your wiring is up to current code.

 

 

 

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Most of my wall outlets are breakered at 15 amps, the kitchen circuits are 20.  the reason for my asking is that I don’t want to run over about 70% of 15 for long periods of time. It’s a little like you don’t want to run your car at redline all the time.

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A typical laptop wall-wart is 65 to 130 watts.
Once the system is up, it usually draws far less.
Systems with solid state disks draw less startup current, because there are no disks to spin up.
HWMonitor is freeware that will show your system power draw.

Drawing a steady 10.5 amps is a 1260 watt draw on a 120v nominal circuit.
Think of the heat a 1260w bulb will generate.

If you are not getting a warm plug, your operating current is probably a lot less than 10.5 amps.
I run two servers and an i7 desktop off the wall plug, plus an occasional client machine and monitor on the bench.
The whole front of the house is on this single circuit, and only an electric heater or hair dryer (both at same time) trips the breaker.


 

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Everything you have plugged in should have the max amperage draw on a tag on the device. Or you can look the specs up on line. Add up the numbers and see what you get.

 

Shade tree mechanic way to tell if you are pulling too much power on one cord is “heat”. If your plug or cable near the outlet is warmer than the surrounding area then you are pushing it with the power draw...in some cases.

 

You could spend a couple hundred bucks on a fairly good clamp on ammeter or you could get this (for household low power use) from Harbor Freight. 

https://www.harborfreight.com/digital-clamp-meter-96308.html

 

It isn’t anything I would use at work but for just getting a close ballpark measurement I am sure it would be fine for what you need.

 

Believe it or not I had a Harbor Freight multimeter that I used for continuity tests because it had a loud beeper that worked just as well as my Flyke meter in regards to measuring accuracy. I never truly trusted it but it was good for ballpark measurements.

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14 hours ago, Marshal Mo Hare, SASS #45984 said:

I have. Power strip with 4, sometimes 5, laptops plugged into it, plus a couple monitors, speakers, external hard drives. I’d like to know what its maximum power draw is. If it’s close to the limits of the wiring, I will reorganize things. Does anyone do this, have recommendations?

Most residential wall circuits are breakered at 15 amps.

I suggest you look into a surge protected power strip.

Each device is required to have circuit load info on it. 

OLG

 

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17 hours ago, Marshal Mo Hare, SASS #45984 said:

I have. Power strip with 4, sometimes 5, laptops plugged into it, plus a couple monitors, speakers, external hard drives. I’d like to know what its maximum power draw is. If it’s close to the limits of the wiring, I will reorganize things. Does anyone do this, have recommendations?

 

I bought an AC line splitter and a clamp on meter.  You'll probably need a better quality meter to get a maximum current.  I think this was the line splitter.  I can't remember which clamp on I used, but I had a decent one for work. 

 

https://smile.amazon.com/Tacklife-Classic-Splitter-Voltage-Accessories/dp/B07533GZTK/ref=sr_1_4?crid=347BUWYDYD2RH&keywords=ac+line+splitter&qid=1563229184&s=gateway&sprefix=ac+line+splitter%2Caps%2C170&sr=8-4

 

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47 minutes ago, Ramblin Gambler said:

 

I bought an AC line splitter and a clamp on meter.  You'll probably need a better quality meter to get a maximum current.  I think this was the line splitter.  I can't remember which clamp on I used, but I had a decent one for work. 

 

https://smile.amazon.com/Tacklife-Classic-Splitter-Voltage-Accessories/dp/B07533GZTK/ref=sr_1_4?crid=347BUWYDYD2RH&keywords=ac+line+splitter&qid=1563229184&s=gateway&sprefix=ac+line+splitter%2Caps%2C170&sr=8-4

 

So, something like that and a meter?  The price range of this and the other Harbor Freight item looks good. I’m not looking for “four digit accuracy”. (That’s a joke among woodworking instructors that I have known). I do shy away from product descriptions written by Chinese DAMHIKT but this looks like it will do the job, thanks.

 

it looks like I can answer the question for under $30 with a reasonable degree of accuracy.

 

FWIW, the power strip has 12 outlets and 3 USB ports.the 12 outlets have 8 things plugged in and because of the size of those things there is no room for more but two of the “things” plugged in are twofers (plugs that split into two plugs). At the moment 11 things are plugged into it. Yes, I can add up all of the numbers from each device, laptop, HDD, speaker, monitor. But I do not necessarily believe those numbers, I was in the industry too long.  In the forgotten words of detent, “trust but verify”

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If you are going to do an "amp draw" with a clamp on meter, you'll have to take the panel cover off and measure the load on the wire leaving the breaker itself. Otherwise, get a true amp load of your equipment at the source, you'll have to take the receptacle out of the wall and measure the incoming line wire.

 

Gonna be easier to add up the amps on the equipment itself. If the listing on the equipment is in wattage, take the wattage and divide it by the voltage (120v) to come up with amperage. Most plug strips have the listing for the mini-breaker listed at the mini-breaker, note: this is not the on/off switch. Keep in mind that even though the equipment might add up to over what you would like to see, it is all rarely (if ever) running all at the same time at max amperage.

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20 hours ago, Marshal Mo Hare, SASS #45984 said:

Most of my wall outlets are breakered at 15 amps, the kitchen circuits are 20.  the reason for my asking is that I don’t want to run over about 70% of 15 for long periods of time. It’s a little like you don’t want to run your car at redline all the time.

The circuit breakers in power strips & house distribution panels are rated for 80% of their rating continuously & 100% for 3 hours.  This applies for ambient temperatures of 104F (40C) at up to 3300 ft. (1000 meters).  The overload element is bimetal which when under heavy load weakens & trips at lower & lower current levels.

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