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wire size

jask

Well Known Member
My RV-6a does not have a ground wire to the regulator. It is using a 1976 honda alternator. The regulator was changed by a previous owner to a VR166 with some wiring changes. I have a new VR166 to install and noticed that the case of the regulator was grounded through the air frame. What size wire should I use to ground the regulator and at what point should I ground to on an 0-360.
 
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The regulator that failed was on for 4 years until it began pulsing from charge to not charging. I see that a ground is recommended and thought it might help.
 
The regulator that failed was on for 4 years until it began pulsing from charge to not charging. I see that a ground is recommended and thought it might help.

Most istallations consolidate all of the grounds on the firewall. If the VR is mounted to the firewall, I see no need for a separate gound wire My planes don't have one for the VR and have never had an issue. Dielectric grease between the VR and firewall may help prevent corrosion issues, but shouldn't be an issue here, as firewall is stainless most VR's are zinc plated or chomed.

Many folks on this site seem very against frame grounding and not sure why. Frame grounding has worked well on 100's of millions of cars, assuming corrosion issues are dealt with. Clearly there are exceptions for noise sensitive equipment.

Larry
 
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The regulator that failed was on for 4 years until it began pulsing from charge to not charging. I see that a ground is recommended and thought it might help.

My personal opinion and others may disagree but airframe grounding (as long as corrosion issues are dealt with) is a perfectly acceptable way to ground. I would ground most avionics and all audio related gear to the correct of tabs to keep ground loops at bay but other things I have no issue with local airframe grounding.
 
If there is a good electrical bond between the alternator frame and the engine case (steel alternator mounts normally provide this), and there is a ground strap bond from the engine case to the airframe, and a good clean bond between the regulator mount and the airframe (no paint on the airframe where the regulator bolts on), then you should have a proper ground path.
You can check this with an Ohm meter.
If you feel the need for an additional ground wire, it should run from the regulator mount all the way to the alternator frame. 10 AWG wire should be adequate.
 
If you feel the need for an additional ground wire, it should run from the regulator mount all the way to the alternator frame. 10 AWG wire should be adequate.

The VR only passes field current, not output current. Most use a 5A CB for this field current, so 20 gauge would be more appropriate for VR grounding than 10 Ga.

Larry
 
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