Flex ware inverter bypass slide [RE-wrenches]

[boB Gudgel]

Mark Frye wrote:
> 
> The issue of the door grounding is interesting and the devil is in the 
> details.
> 
> Yes,a ground wire from the inverter to ground buss will ground the 
> inverter, but what about the sheet metal of the door itself.  This a 
> piece of conductive material that could become energized, and must be 
> properly ground at all times, door open or door closed.

I would use a screw with star washer to make sure the inverter is 
connected electrically to the door, or backplate or whatever it is 
mounted to.... Not just E-Panels.

boB


> 
> A standard method is to install a stud into both the door and the box 
> and use a braided ground strap to bond the door (see most Hoffman 
> enclosure with hinged doors).
> 
> Unless the door is properly bonded to the inverter chassis by some 
> specific method, it sounds like the MidNite falls short in meeting this 
> requirement.
> 
> boB Gudgel wrote:
> > 
> > 
> > From Robin:
> > 
> > Ain’t competition grand? Some of us handle it better than others I 
> > guess.
> > I will address the issues that were brought up.
> > 
> > AC bypass switch: This is a transfer switch. It does not need to be made 
> > 
> > 
> > with circuit breakers. The MidNite bypass switch operates very smoothly 
> > indeed. This is not an easy task.  The AC bypass switches I designed at 
> > Trace engineering, OutBack and MidNite are all similar, but slightly 
> > different. They all meet the UL requirements and they all function 
> > properly. It becomes a personal preference, not a safety or a NEC issue. 
> > 
> > 
> > Transfer switches are not required to turn both circuits off at the same 
> > 
> > 
> > time. Store bought transfer switches like the Square D at Trace work 
> > like the MidNite bypass switch. 
> > 
> > Separate bypass switches: This style of bypass is not as convenient as 
> > one that operates two or more inverters at the same time, but it is not 
> > a safety issue. Fifty thousand bypass switches that work like the 
> > MidNite bypass have been installed from Trace, Xantrex, OutBack and 
> > Midnite over the last 13 years or so.  Remember, we use breakers in 
> > place of the switches, so in the unlikely event that something went 
> > wrong, the breaker would trip. I am not aware of a single instance where 
> > 
> > 
> > this style bypass switch led to a problem. In a previous post, I 
> > mentioned an upcoming product that addresses the issue of single vs. 
> > dual vs. quad bypass switches. What this means is that you will have 
> > more choices available soon for larger systems. 95% of the E-Panel 
> > installations have been single inverters. Dual E-Panel installations do 
> > not yet have such a clear cost advantage over the competition as the 
> > single E-Panel installs. 
> > 
> > Another accusation about our bypass switch has to do with moving both 
> > the inverter output and the bypass breaker together at once. This is the 
> > 
> > 
> > way we did it for years at OutBack and how it is now done at MidNite. 
> > The OutBack bypass switches on dual and quads were changed to the 
> > present configuration while I was still president of OutBack. I actually 
> > 
> > 
> > made those changes. The reason for the change had nothing to do with 
> > safety. We just couldn’t get all the tolerances down to make a smooth 
> > operating switch, so we opened up the slots. This forces the user to 
> > manually turn the one switch on after flipping the slider. It also 
> > allows both breakers to be turned off. Either method is ok. NEC requires 
> > 
> > 
> > a separate generator disconnect box if the generator is not within site 
> > or is remote. This is more convenient and more obvious as the AC input 
> > disconnect if done separately. My electrician installed a separate 
> > generator input disconnect before the PS2 panel to meet code since my 
> > generator is remotely located. The PS2 can turn off both breakers at the 
> > 
> > 
> > same time, but my electrician did not believe this was adequate. Some 
> > installations do not require a separate generator disconnect due to 
> > proximity. 
> > 
> > One more thought comes to mind to disconnect power…… How about turning 
> > the inverter off! Use the big DC breaker or the inverter on/off switch. 
> > The output is then isolated by the contacts inside the inverter relay. 
> > Some installers add a 50 amp output disconnect breaker inside the 
> > E-Panel when needed. This is another way to create a clearly labeled 
> > method to disconnect the house loads. Since the issue here is to make 
> > sure there is no power going to the house loads it would be wise to turn 
> > 
> > 
> > the generator off before working on the system. As discussed here, there 
> > 
> > 
> > can be disconnects installed before or after the power source. This is 
> > not a requirement of the E-Panel to meet code. Thousands of E-Panels 
> > have now been installed and inspected without issues.
> > 
> > Door grounding: The comment about our system being unsafe due to no 
> > ground is false. Has anyone ever heard of putting a ground wire from the 
> > 
> > 
> > equipment ground terminal on the inverter to the ground terminal in the 
> > breaker box? All E-Panel doors come with a wiring diagram that clearly 
> > shows the inverter grounded. Screws and star washers ground the inverter 
> > 
> > 
> > to the chassis when shut, but to insure grounding while the door is 
> > open, you should install a 6awg green THHN ground wire (follow the NEC 
> > code). Equipment grounding is always required. 
> > 
> > Cabling: The cables that run from the battery breaker and shunt to the 
> > inverter do not loosen up. This issue was addressed at the beginning 
> > with ETL before I started designing the E-Panel. The statement that our 
> > design is going to cause a fire is just not true. The E-Panel is a 
> > different kind of breaker box. I knew people would be taking pot shots 
> > at it, so ETL and I reviewed the cabling and wiring issues early on. 
> > This is not something that was slipped by the ETL inspector while he 
> > wasn’t looking. I have been working with this same ETL engineer for over 
> > 
> > 
> > a dozen years and believe me; he does not let anything through that does 
> > 
> > 
> > not meet UL standards. Most of the Trace Engineering equipment, lots of 
> > Xantrex, all of the OutBack, all of the Magnum, most of the PV Powered 
> > and all of the Midnite products were evaluated by Tony Dorta of ETL. 
> > Tony is very respected by manufacturers in the RE industry.
> > 
> > The MidNite E-Panel does not hold as many breakers as other boxes. That 
> > is true. The Stretched OutBack E-Panel will accept up to 6 additional 
> > field installed din rail mount breakers and two panel mount breakers in 
> > addition to the AC bypass, AC input and inverter battery breaker. The 
> > stretched OB E-Panel has mounting for up to four shunts at once.
> > 
> > Competition is good. False accusations are not. Per the moderator’s 
> > request, this is a one time response. I consider this thread closed.  
> > The market is pretty good at sorting out what they like. 
> > I thank you for your support, past, present and future.
> > Robin Gudgel
> >  
> 
> 
> 
> Berkeley Solar Electric Systems



boB Gudgel K7IQ
MidNite/Magnum  Solar/Energy
Washington AC


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