Well, that call was enlightening. I told the support guy about the 350kcmil reference ground and he laughed, then he said to someone next to him, "Doug! This guy's got a contractor telling him he needs a 350 reference ground! Hah!" They actually say to use the larger of 10AWG or the largest power conductor on the system, which makes a hell of a lot more sense. I told him the story from the former Comcast guy about every Comcast site having the honking big wire to MGB and 2AWG to earth, and he said Comcast can write whatever spec they want, and if they want to waste all that copper that's their business.
So yeah, people are doing this weird thing, and it sounds like Ken's option #5 is the reason. They have no idea why they do it. -Adam ________________________________ From: AF <[email protected]> on behalf of Ken Hohhof <[email protected]> Sent: Thursday, February 5, 2026 1:25 PM To: 'AnimalFarm Microwave Users Group' <[email protected]> Subject: Re: [AFMUG] Reference ground sizes I can think of 4 general explanations that might fit: 1) current carrying capacity 2) ground potential difference 3) safety of equipment or personnel in some fault condition 4) some regulation or code that may not make sense but you have to follow it just because Our guesses are probably not going to be helpful, I would ask your low voltage guy where this spec comes from. It seems very specific, it must come from somewhere. If he says it’s in the GE installation manual, I would ask GE. OK, there’s another possibility #5, it’s what they’ve always done and he doesn’t know why. From: AF <[email protected]> On Behalf Of Steve Jones Sent: Thursday, February 5, 2026 11:59 AM To: AnimalFarm Microwave Users Group <[email protected]> Subject: Re: [AFMUG] Reference ground sizes My guess would be so that the fire starts aways from the rectifier and not at it. Not saying there is an inherent fire risk. But it takes the detrimental load away to a far off point of failure. On Thu, Feb 5, 2026 at 9:44 AM Adam Moffett <[email protected]<mailto:[email protected]>> wrote: When we get big rectifiers installed, the low voltage guy is running a 350kcmil to the MGB. 350kcmil is about 7/8" diameter including the jacket. It feels kind of silly to have that on the bus bar and have a #2 to earth, but I'm told this is normal. What's the point of having that anaconda from the rectifier to the bus bar? These are GE Infinity systems by the way. 16KW to 32KW systems. -Adam -- AF mailing list [email protected]<mailto:[email protected]> http://af.afmug.com/mailman/listinfo/af_af.afmug.com
-- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com
