this doesnt seem safe or right to me

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ok guys, question for you. theres a job site im on that a welding company is doing some welding in the main trusses throughout the building. they are clamping their ground to the steel studs just inside the door of the building and then doing all of their welding hundreds of feet away. this doesnt sound safe or right to me. how about you guys? i was always taught that you keep the clamp as close to the work as you canMillermatic 211weldpack 3200 squirtgunsquare wave 200victory journeyman kitHypertherm 30xptoo much other crap to listtinkerer extraordinaire
Reply:Rebuilt a few boilers in a Alcoa plant and those welder's only walked with a stinger
Reply:Its done all the time IMO not a problemI always tried to work with the oldest hand on the job to gain knowlege but now I can't find any.
Reply:As resistance is added to the CC welding circuit, the power supply has to output higher voltage to maintain the constant current flow through the restricted circuit.  It seems like they could run into a situation where poor conductivity through the long distance steel work of the building would cause the welding power supply to output abnormally high voltage to maintain constant current, and this could lead to overheating and strain on the equipment if a motor generator unit, or undue power power draw if a line feed system.
Reply:That is how I have seen it done at all the power plants I have worked at. In the shop at work we have a "4 pack" of Miller 304s with a large copper bus bar bolted to an I beam, and all 4 machines grounded (bolted) to the bar. The machines work a bit harder, but the wear and tear on the machines is off set by the saved time / labor costs when you need to run 300 foot of lead safely, without tripping hazards, multiple times a day. The only time we really run both leads is when we are welding near large motors or instrumentation.Just another clown trying to be cool
Reply:I install Manlifts in to grain terminal. Done there all the time, The job I am on now they clamped on to the botton main rail of the manlift and ran the stinger up the hoist way 160 ft  to weld the machine base down.Lincoln 175spLincoln 350MP
Reply:Thats pretty normal. When piping up a new building we ground to the closest beam or column, and carry a jumper made from a 10-20 foot section of lead with ground clamps on both ends to do work on pipe stands. Shipyards do it this way too. Lots of utility tunnels have hot lead run through-out and everything is grounded.
Reply:Originally Posted by kmaysob i was always taught that you keep the clamp as close to the work as you can
Reply:As far as safety is concerned, you have no worries.As far as weld quality, you're more likely to see arc blow and reduced output due to the resistance in steel as opposed to the copper leads.CWI, CWE, CST for Miller, Lincoln, Thermadyne, Hypertherm & ESABMillermatic 350PLincoln Invertec 205 AC/DCVictor combo torchESAB PCM 1125
Reply:DO it darn near every day.    I have ran over 1000 feet of electrode lead with less than 25' of work lead (ground).For the FCAW welding that i do mainly its electrode negative.    You DO have to compensate for the amount of resistance in the line by turning up the machine.  The vantage 500's simply don't care at all.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:Originally Posted by pulserAs resistance is added to the CC welding circuit, the power supply has to output higher voltage to maintain the constant current flow through the restricted circuit.  It seems like they could run into a situation where poor conductivity through the long distance steel work of the building would cause the welding power supply to output abnormally high voltage to maintain constant current, and this could lead to overheating and strain on the equipment if a motor generator unit, or undue power power draw if a line feed system.
Reply:Its not a problem in an all steel structure, but once the shortest path to ground goes through some electronics or pump bearings you will ruin them. It is a common practice but your ground should be as close to your work as possible. It becomes a safety issue later when something in a building system fails and causes injury because of the current that passed through it previously.UA Local 598