amperage question regarding computers - Electrician Talk - Professional Electrical Contractors Forum

BuzzKill · 07-12-2009, 07:14 PM

What's the average computer workstation pull, amperage wise? That's with a generic 17" flat screen and a normal printer included.

Magnettica · 07-12-2009, 07:17 PM

Id say anywhere from 300-500 watts.

**MDShunk** · 07-12-2009, 07:33 PM

If by "normal printer" you mean something other than a laser, I'd agree that 300-500 watts would be a good figure.

BuzzKill · 07-12-2009, 07:57 PM

Exactly. I got a small job to put 5 workstations on a dedicated circuit in some old commercial building. Whole work space runs off one 20 amp breaker that keeps tripping. I might run two for robustness-sake, incase a stray vaccum cleaner gets plugged in.

**MDShunk** · 07-12-2009, 08:00 PM

Quote:

Originally Posted by BuzzKill

Exactly. I got a small job to put 5 workstations on a dedicated circuit in some old commercial building. Whole work space runs off one 20 amp breaker that keeps tripping. I might run two for robustness-sake, incase a stray vaccum cleaner gets plugged in.

Good choice. If it's not a sweeper from the night janitorial, it will be one of those little heaters people put under their desks.

BuzzKill · 07-12-2009, 08:13 PM

It's a sad situation; I'd hate to do any troublewhooting there, the work is hap-hazard and been through dozens of remodels. One worker told me that when she prints at the same time her co-worker does, it trips the breaker, that and the vaccum cleaner pops it too. With just two workstations going the 20 amp for their space was running 17 amps in the panel.

cguillas · 07-12-2009, 09:42 PM

That's not surprising. My desktop laser printer (not even a big copier) draws 12A on it's lonesome.

**MDShunk** · 07-12-2009, 10:11 PM

Quote:

Originally Posted by cguillas

That's not surprising. My desktop laser printer (not even a big copier) draws 12A on it's lonesome.

Yeah, laser printers are power hogs for short bursts. My big server only draws 900 watts, but the laser printer pushes the needle toward 20 amps.

Mr. Sparkle · 07-12-2009, 10:22 PM

Quote:

Originally Posted by cguillas

That's not surprising. My desktop laser printer (not even a big copier) draws 12A on it's lonesome.

Wow, I had no idea......mental note.

chenley · 07-13-2009, 07:19 AM

Have ran into that problem with a small UPS and did a little research. Laser printers are amp hogs, and with all printers it is the paper feed which kicks up the amperage so much.

Had a 1000W UPS on a dedicated circuit that would kick off when printing. Only the printer, monitor and PC were plugged in. Turns out installing a powered USB hub fixed that problem. I still have no idea why it drew that much amperage through the USB and not the power supply, but it did.

drsparky · 07-13-2009, 07:28 AM

Quote:

Originally Posted by chenley

Have ran into that problem with a small UPS and did a little research. Laser printers are amp hogs, and with all printers it is the paper feed which kicks up the amperage so much.

Had a 1000W UPS on a dedicated circuit that would kick off when printing. Only the printer, monitor and PC were plugged in. Turns out installing a powered USB hub fixed that problem. I still have no idea why it drew that much amperage through the USB and not the power supply, but it did.

UPS can be tricky this page explains a lot.http://www.apcmedia.com/salestools/S...NQYL_R0_EN.pdf

brian john · 07-13-2009, 07:36 AM

Quote:

Originally Posted by MDShunk

Yeah, laser printers are power hogs for short bursts. My big server only draws 900 watts, but the laser printer pushes the needle toward 20 amps.

I have not measured them in a while but at one time using a high speed recorder the RMS amperage average was between 30-45. This is for the drum heater (a tech told me) and as Marc noted is only for a second or 2 every 30-40 seconds. IN the early days of lasers instantaneous VD was an issue

drsparky · 07-13-2009, 08:09 AM

The "drum heater" is called the fuser, it gets hot fast, I burned my finger tips trying to remove a paper jam years ago.

Toronto Sparky · 07-13-2009, 09:27 AM

Quote:

Originally Posted by MDShunk

Good choice. If it's not a sweeper from the night janitorial, it will be one of those little heaters people put under their desks.

Gotta love those "little" heaters.
I used to get dozens of service calls to banks. When I asked if there are any heaters plugged in they say no..
Then when I point it out to them they say.. Oh it's only a little energy efficient mirofurnace and does not use much power.
Right! 1500W is not much on a 15A circuit with a computer system plugged into it also

Those "little" Heaters tend to blow out the connections in the system furniture too..

Toronto Sparky · 07-13-2009, 09:30 AM

Quote:

Originally Posted by MDShunk

Yeah, laser printers are power hogs for short bursts. My big server only draws 900 watts, but the laser printer pushes the needle toward 20 amps.

Used to love that when your working in a empty building in the middle of the night and you keep see short amperage jumps in the panel..
First though was hey. Who messing with me.

Photo copiers do that too