The BIGGEST mistake you can make in an upgrade is trusting the wrong person or group to do it, either internally, or externally!
"What a Fool Believes" - The Doobie Brothers
"Handy Man" - James Taylor
UNDERSTAND LAIBILITY
Even if management ask you to upgrade a panel...if you do not have the proper training, both the company and you can be sued for liable when someone is injured. Is it worth the risk to save a few bucks?
NEC VIOLATIONS
"Bad Time" - Grand Funk
OK. Let's get real here, if the person doing the work for an upgrade is not certified for UL or OSHA requirements, do you really think they should be doin' the upgrade? That's a negatory good buddy! When this happens, you are setting the organization AND the person doing the work up for LIABILE and placing operators in harms way. You should only trust people with credentials that do the work all the time...and even some of those "professionals" from overseas miss the boat here in the US!
"You Can't Turn Me Off" - High Inergy
Runaway Heat
The most dangerous of all errors involve shorted solid state relays (SSR). Usually this occurs when someone replaces the mercury relays with SSR's and leaves the circuit protection in place. Do to the nature of the SSR vs. Mercury, it will fail in a closed position resulting in a heater band staying on! Bummer!
Rat's Nest Wiring
"Help Me Make It Through the Night" - Sammi Smith
Over time, troubleshooting a panel with issues can leave the wiring in disarray, making it near impossible to troubleshoot the system...adding precious hours to the downtime window. Panels like this are a clear sign of a system desperately needing an upgrade! If you see this inside your panels, your career could end like Disco...in a really ugly way!
"I'm Not Going to Let it Bother Me Tonight" - ARS
Mercury Relays
I mean, you do know this is considered a hazardous material, Dig?! Many states have outlawed them and moving forward, more states are going to follow suit. By the Way, did you happen to read about "Runaway Heats"?! That's where that story begins, Copacetic?
USING CONTACTORS FOR HEAT CONTROL
"You're No Good" - Linda Ronstadt
Does it matter? Duh, are you jelly brained?! Contactors are made for a limited number of mechanical cycles, unlike SSR and Mercury, meaning, over time, they will weld the contacts and create a shorted circuit and runaway heat condition. You should never do this...but we see it out there! Not Cool!
"Hot Blooded" - Foreigner
NOT COOL, DUDE!
When the heat is going up in a panel, the life of the electronics is going down. This usually happens when people replace DC drives with AC drives. They don't know that the AC runs hotter and the current cooling may not be chill!
OSHA/ NEMA Violations
"Couldnt Get it Right" - The Climax Blues Band
There is the old way of doin' things for sure, but that doesn't make them right on! Often these goofs can result in fires or worse, someone getting seriously hurt! Sadly, ignorance of code doesn't excuse misapplication in a court of law. Don't mess with the Man when it comes to Code violations!
"Shop Around" - The Captain & Tennille
Wrong TYPE MOTOR!
Changing your Extruder from a DC motor to AC motor is more than just putting an AC in its place. You need a Vector rated motor and not one rated for VFD's. Also, it must have a constant blower and not just a NEMA motor with fan on the back. Just because some turkey sells drives, doesn't mean they know what to do!
IT FITS! Well...not really!
"Swearin' to God" - Frankie Valli
When changing from DC to AC drives, it seems easiest to stick it back in the same old box! Except the AC drive produces more heat and the box may no longer have proper cooling. Just because it fits (sorta) doesn't mean it was a good idea!
"The Way We Were" - Barbra Streisand
Wrong MOTOR RPM
Speed kills! Well, motor speed doesn't kill, but it can not work! There is a big torque difference between a 300HP/1150RPM motor and a 300HP/1750RPM motor. You can't put a 1750RPM where a 1150RPM was...if you don't know why, you need to be talkin' to us!