Electrical Grounding

[AlienHelix]

Hello everyone.

Looking for any information on grounding of an electrical vehicle. I can't find anything that addresses both grounds (i.e. ground from onboard batteries and electronics, and ground from 120VAC-house when plugged in to be recharged). Looking to see if there is any isolation required. Thanks in advance for the help.

rui

 

[SomeYahoo]

You may want to try CECOM TR-96-6 here:

http://www.monmouth.army.mil/cecom/safety/spub/tr9806.pdf

It has some good information on grounding and boding military vehicles.

 

[CMfgE1]

What type of grounding are you looking to do?
If you could be more specific that would be helpful.

You have the ground or negative for your DC voltage. Your grounding to eliminate any RF interference or noise and grounding to dissipate any electrical "build up" (bleeding).

Just let us know what you are trying to achieve and that will better direct the answer.


Good Luck

Quote: "Its not what you know, its who you know" - anybody trying to find a decent job

 

[AlienHelix]

CMfgE1,

The electrical vehicle has a onboard charger that will plug into a common household receptacle. The question is standards on grounding. Once it's plugged into the house the charger case is grounded, and since its bolted to the frame the frame is also grounded. Just looking for requirements, methods, etc. Once unpluged ground will be floating along with DC(ground -). Basically dealing with two ground systems sort of speak. The DC ground system, and the one that is introduced once plugged into a household receptable.

thanks

 

[SolderingGunslinger]

Since I come from a Radio Frequency Engineering background, my first thought was that it should be a single-point ground, however, upon further reflection; I began to wonder if single-point grounding was necessary.

As far as electrical code goes, I believe, if the charger is an integral part of the automobile, the safety ground must be tied to the frame of the vehicle. If the charger is a removable accessory, then only the chassis of the charger need be tied to the safety ground.

Cases in point:

1. A freeze plug block heater on an internal combustion engine. The ground pin is connected to the body of the heater. After installation, the body of the heater is in direct contact with the engine block, effectively tying the grounding system to the house safety ground,

2. After market automotive trickle chargers. Many have plastic cases and provide no connection to the chassis of the automobile other than through the negative lead (or positive lead on positive grounded vehicles) from the charger to the battery.

I remain,

The Old Soldering Gunslinger

 

[SolderingGunslinger]

Addendum to above:

In many municipalities in the USA, anything which can be hooked into the AC circuit must be listed by Underwriters Laboratories. This is one reason so many devices come with wall-warts and not power cords to be plugged into the AC service.

If you plan to market this in the US, check with the UL

I remain,

Etc., etc.

 

[CMfgE1]

Sounds like you need to develop your own standard.
The only other thing I would consider is installing a GFI (ground fault interupt) in the cord on the AC side of the charger. This would help prevent lawsuits! LOL
And its always a good idea to have one anyways.



Good Luck

Quote: "Its not what you know, its who you know" - anybody trying to find a decent job