Author Topic: MTU red wire - when do you use it?  (Read 2401 times)

n8huntsman

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MTU red wire - when do you use it?
« on: April 21, 2013, 09:10:06 PM »
When do you wire the MTU for 120 vs 240?  I'm unsure when you would use the red wire and when you shouldnt.  Google searches pull up two different pdf manuals.  One says wire it for 120 (cap the red) the other shows to wire it for 240 (red to one pole, black to the other).  Here are the links:
http://files.theenergydetective.com/QuickStart-Installation%20v110510.pdf

http://www.theenergydetective.com/downloads/QuickStartInstallation%20v110711.pdf

If one is outdated, it should probably be removed to prevent confsuion.

Thanks.

Canada_Guy

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Re: MTU red wire - when do you use it?
« Reply #1 on: April 24, 2013, 08:34:31 AM »

From what I can tell, you can use both the red and black wires on opposing hot legs as long as you don't have communications issues with your gateway. If you do have communications problems, cap off the red wire and ensure the gateway is on the same power leg as the black wire. Not using the red wire increases data signal levels.

Here are a few threads about the red wire:

http://www.theenergydetectiveforums.com/index.php/topic,810.0.html

http://www.theenergydetectiveforums.com/index.php/topic,1333.0.html

http://www.theenergydetectiveforums.com/index.php/topic,15.msg23.html#msg23  (see note#2)

RussellH

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Re: MTU red wire - when do you use it?
« Reply #2 on: April 25, 2013, 08:52:14 PM »
Not using the red wire increases data signal levels.

It increases the signal level on the phase it's connected to. 

Using the Red wire gives you signal in both phases.
It also allows you to average the voltage of the two phases.