Did an install in a theater in the heart of downtown Toronto. As we've discussed several times before, a happy job site is one with great communications between the various, trades, authorities and departments.
This particular project involved somewhere in the area of 17 A/V racks, 14 at 44 RU and three shorter racks, one wall mounted and two rolling / portable. The electricians had at least 6 more 44 RU racks not counting dimmers. Where it got particularly silly was DSR and DSL at deck level where there were four 44 RU racks immediately adjacent to each other on both sides of the stage. The electrical consulting PEng demanded his racks be grounded to the building's electrical ground and rightly so with no one arguing. The electro acoustics PEng wanted his rack on each side also bonded to the same ground as the other three adjacent racks on each side as he knew the equipment being housed in those two racks had separate connections brought out for chassis and circuit grounds. When the electricians assembled and installed their three racks per side, we bolted our identical rack to theirs on both sides of the stage. Then it got silly. The electro acoustics PEng was happy but the Electrical consulting PEng decreed we had to install a non-conductive solid barrier wall between our rack and his racks and bolt the racks together with non-conductive nylon hardware. Try as we might, we COULD NOT get the two consulting PEng's to speak to each other thus it came to be we unbolted our racks from theirs, pried them apart, wedged in a flat, laser cut, insulating barrier panel, re-bolted the racks together with threaded nylon hardware AND installed two redundant bonding jumpers between the adjacent racks to ensure they both were at a common ground potential. Sometimes it just gets silly and then there are times when it gets even sillier. That was plenty silly enough. Don't get me going on architects. Don't do it. You've been warned.
Back to the above racks and their grounding.
The electro acoustics PEng felt he was better off to ground his rack to the electrician's ground, ground his rack mounted chassis to their ground and only tie his circuitry to the dedicated audio ground knowing full well it would be a pointless futile exercise to try to keep his entire rack at audio ground and have to track down intermittent problems whenever anyone leaned a length of pipe across the insulated gap between the racks or rolled a metal trimmed road case against the racks.
The electrical consulting PEng was so set in his ways / so certain the A/V rack would be at A/V isolated ground potential, he wouldn't even consider any other point of view, hence we ended up playing the game and having an expensive laser cut non-conductive barrier fabricated for both sides of the stage.
@BillConnerFASTC You've NEVER experienced any electrical consulting PEng's like that have you? I'll just bet you've met more than one by now.
Toodleoo!
Ron Hebbard.
This particular project involved somewhere in the area of 17 A/V racks, 14 at 44 RU and three shorter racks, one wall mounted and two rolling / portable. The electricians had at least 6 more 44 RU racks not counting dimmers. Where it got particularly silly was DSR and DSL at deck level where there were four 44 RU racks immediately adjacent to each other on both sides of the stage. The electrical consulting PEng demanded his racks be grounded to the building's electrical ground and rightly so with no one arguing. The electro acoustics PEng wanted his rack on each side also bonded to the same ground as the other three adjacent racks on each side as he knew the equipment being housed in those two racks had separate connections brought out for chassis and circuit grounds. When the electricians assembled and installed their three racks per side, we bolted our identical rack to theirs on both sides of the stage. Then it got silly. The electro acoustics PEng was happy but the Electrical consulting PEng decreed we had to install a non-conductive solid barrier wall between our rack and his racks and bolt the racks together with non-conductive nylon hardware. Try as we might, we COULD NOT get the two consulting PEng's to speak to each other thus it came to be we unbolted our racks from theirs, pried them apart, wedged in a flat, laser cut, insulating barrier panel, re-bolted the racks together with threaded nylon hardware AND installed two redundant bonding jumpers between the adjacent racks to ensure they both were at a common ground potential. Sometimes it just gets silly and then there are times when it gets even sillier. That was plenty silly enough. Don't get me going on architects. Don't do it. You've been warned.
Back to the above racks and their grounding.
The electro acoustics PEng felt he was better off to ground his rack to the electrician's ground, ground his rack mounted chassis to their ground and only tie his circuitry to the dedicated audio ground knowing full well it would be a pointless futile exercise to try to keep his entire rack at audio ground and have to track down intermittent problems whenever anyone leaned a length of pipe across the insulated gap between the racks or rolled a metal trimmed road case against the racks.
The electrical consulting PEng was so set in his ways / so certain the A/V rack would be at A/V isolated ground potential, he wouldn't even consider any other point of view, hence we ended up playing the game and having an expensive laser cut non-conductive barrier fabricated for both sides of the stage.
@BillConnerFASTC You've NEVER experienced any electrical consulting PEng's like that have you? I'll just bet you've met more than one by now.
Toodleoo!
Ron Hebbard.
