What Happens To EMS During Start With Bad Ground

[Dynon101]

I started a new thread for this question that was introduced on another post:

What happens if the main negative cable to engine block ground connection is loose or corroded and the starter is engaged...this large amount of current will want to flow down any path it can find so what protection is there in the EMS to prevent huge power surges through the EMS wires/pins?

 

[jakej]

See my previous post.

 

[Dynon101]

Jake J thanks for the reply

I still have the question... what protection is there in the EMS to prevent huge power surges through the EMS wires/pins?

Does this imply that there is no protection and that the EMS will. burn up?

 

[jakej]

Ok- if you face a situation where the main ground from engine to the ground bus is lost in a plastic plane then it won't start as there is generally no ground return path- unlike a 'metal' plane which can use control cables etc as they are attached to the airframe, then there can be issues like control cables seizing up etc.
As I've said previously - use 2x ground straps, they MAY be considered overkill but you won't have any grounding issues that way.
Grounds to items like the Dynon, I'll try to explain simply - the wires go to the boxes but don't actually go directly to grounds there is no way they act as a ground path in the situation you are asking about.

 

[rogersmart]

I worried about this when I built my plane so I connected the engine block to the battery with one cable and the airframe to the engine block on a separate cable to a separate bolt on the engine block. I believe this eliminates the possibility of a ground path through anything on the airframe since airframe's ground comes only from the engine block.

 

[jakej]

Exactly !

 

[Dynon101]

THANKS guys...I GREATLY APPRECIATE your help!!!