external power
 

having the switch constantly engaged in the cockpit and then the ramp workers turning on external power that may not be plugged in correctly or outputting correctly has the potential to ... a) create a power short that could.. wait for it.. kill the guy plugging it in.... b) **** up the airplane power contactor..... I could care less personally about changing a million power contactors.. but if we kill a rampee because we don't push a button anymore for ease of whatever... someone who passed a bar exam at some point in their life might have some questions to ask after someone else puts their hand on a bible... just sayin

Do you have any evidence that plugging in external power can kill someone, or did you just pull that out of your butt like 95% of the posts on this website?

external power
 

next time you are in dtw come to the 9e mx office and will show you the entry and exit wounds I have from 480volts going in one hand through my body and out the other.. and oh yeah.. that's right... 30 years of aircraft maintenance on my resume.. anyway.. keep your button selected and wear your hat

From a MX standpoint, plugging ground power in with the APU gen on does nothing. The relay from the GP is open, and nothing flows. And if the APU gen is off, then so should everything else be in the plane, so plugging in will only draw a little power for the battery bus and battery utility bus. Unless I am missing something, I don't see it as an issue from an electrical/MX point of view.

And the GPUs don't put out 480V. And if there WERE to be a feeder fault (highly unlikely, but possible), the GCU would open the circuit immediately to prevent damage to the plane.

Feeder fault, under voltage, over voltage, under freq, as well as correct phase rotation are all features of the GCUs as I recall.

There is no way I will leave that switch pushed in.
It has caused many issues in the past. We have never left it pushed in why would we start now and what good does it do. Nothing

external power
 

the input power to gpu is 480 volts so gather yourself some additional facts and I am sure you have ata 24 on lock down so you guys select or don't select any button you feel like.. I will just be sure to let everyone in mx know to deselect in the cockpit first... It does have the potential to kill someone and damage the aircraft regardless of what Thomas Edison had to say previously... with that.. I digress

If the APU GEN is on, and the switch is out, how much power flows when connecting the AGPU? What about if the switch is in?

external power
 

2 senior lead mechanics.. 2 senior line mechanics and 1 avionics tech currently in the gate office.. we all agree leaving that switch permanently selected can only lead to trouble... had johnny gone to the police right away... none of this would have ever happened..... I honestly like the thread about the bow/cg having to be adjusted on the entire fleet due to efb and no more crew bags

Totally agree with the Mx guys on this one

Isn't this what caused the fire in pvd? The switch was left in and a bad gpu was plugged into the bird and someone left the switch in? The power would go on and off and on again over and over until bad things happened.
Could be wrong but I think that was it.

Don't leave the switch in regardless.

Sounds to me like MX and Standards needs to have a serious discussion about this then.