gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
120713-1252 EDT
For easy reference here is a copy of the original post:
kwire:
I agree if one MWC is supplied to the room the implication is that one EGC is common for the majority of the path, and that for most conditions won't create a problem with respect to the EGC. My comments were meant to show what happens if non-common neutrals were used.
What do large printers and plotters mean in the OP? I doubt a 1 HP motor is in the printer or plotter, but we need more information on what the real loads are expected to be.
If the printer is a large Xerox production book printer, then it might even require 240, or 3 phase.
Depending upon the equipment neutral harmonic content consideration is needed. Your comment on the open neutral does suggest a reason to avoid an MWC.
iwire:
I have a small Epson printer with USB communication and a 3 prong AC plug.
In one spot I have 4 desktop computers and an HP LaserJet 5 Si MX all on the same 20 A circuit. The heater in this printer is mostly an on-off device with large power spikes for short durations. I have no problems from the voltage variations from these pulse power loads, and no need for multiple circuits.
Unless a communication path signal has built in isolation it almost certainly is referenced to the machine chassis, and thus to the EGC. True of big CNC machines.
.
For easy reference here is a copy of the original post:
kwire:
I agree if one MWC is supplied to the room the implication is that one EGC is common for the majority of the path, and that for most conditions won't create a problem with respect to the EGC. My comments were meant to show what happens if non-common neutrals were used.
What do large printers and plotters mean in the OP? I doubt a 1 HP motor is in the printer or plotter, but we need more information on what the real loads are expected to be.
If the printer is a large Xerox production book printer, then it might even require 240, or 3 phase.
Depending upon the equipment neutral harmonic content consideration is needed. Your comment on the open neutral does suggest a reason to avoid an MWC.
iwire:
I have a small Epson printer with USB communication and a 3 prong AC plug.
In one spot I have 4 desktop computers and an HP LaserJet 5 Si MX all on the same 20 A circuit. The heater in this printer is mostly an on-off device with large power spikes for short durations. I have no problems from the voltage variations from these pulse power loads, and no need for multiple circuits.
Unless a communication path signal has built in isolation it almost certainly is referenced to the machine chassis, and thus to the EGC. True of big CNC machines.
.