Article 720

[cosmos]

What are typical applications for this article, and why must receptacles be rated not less than 20amp?

 

[Hendrix]

720.6 and then 720.7

 

[cosmos]

I was just curious as to what systems less than 50volts, this article was tailored for - batteries?

 

[Hendrix]

I was just curious as to what systems less than 50volts, this article was tailored for - batteries?

AC/DC is what the article is about.

 

[tom baker]

Article 720 dates from the 1930s when farms were being electrified with 32V DC Delco power plants, there are several good web sites with restored light plants.
The delco salesman would come out at night and demonstrate the lightp plant to the wife, and then she wanted one.
The light plant automatically started to maintain the charge on the battery bank.
So its basically a DC power system. The article could be used today for a PV system.
I guess the reason the receptacles are 20A is due to the heavier DC load at 32V.
Its the shortest article in the NEC.

 

[cosmos]

Thanks Tom. Besides myself, does anyone think that it would be helpful if the Code, or the Handbook, would preface each Article with its origin and intent?