• We will be performing upgrades on the forums and server over the weekend. The forums may be unavailable multiple times for up to an hour each. Thank you for your patience and understanding as we work to make the forums even better.

2020 NEC 250.25

Status
Not open for further replies.
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Not sure what this is about-- wrong article #???

250.25 Grounding Systems Permitted to Be Connected on the Supply Side of the Disconnect.

The grounding of systems connected on the supply side of the service disconnect, as permitted in 230.82, that are in enclosures separate from the service equipment enclosure shall comply with 250.25(A) or (B).

250.25(A) Grounded System.

If the utility supply system is grounded, the grounding of systems permitted to be connected on the supply side of the service disconnect and are installed in one or more separate enclosures from the service equipment enclosure shall comply with the requirements of 250.24(A) through (D).

250.25(B) Ungrounded Systems.

If the utility supply system is ungrounded, the grounding of systems permitted to be connected on the supply side of the service disconnect and are installed in one or more separate enclosures from the service equipment enclosure shall comply with the requirements of 250.24(E).
Click to expand...
 
S

shortcircuit2

Senior Member
Location
South of Bawstin
Sorry...for 2...maybe 3 Code cycles there has been confusion, debate (numerous threads here), and argument across the country on whether a supply-side connected PV Disconnect needed to have a Main Bonding Jumper per 250.24(B) like a Service Disconnect. But...a PV disconnect is not a "Service Disconnect", nor is a PV system a "Service", CMP 4 asserted. With the new section 250.25 in the 2020 NEC, the language now requires the Main Bonding Jumper to be installed per 250.24(B)...and also requires the installation to comply with 250.24(D) and the installation of a GEC to the enclosure for systems connected supply-side of the service disconnect as permitted in 230.82. {For the rarely installed supply-side ungrounded service interconnection, follow 250.24(E)}

A 705.12 (705.11 in the 2020) supply-side connected Interconnected Power Production Source is exposed to the same dangerous fault currents that a service disconnect is, so it is important to bond and ground like a service disconnect.

I can not think of a arrangement when following 250.24 (A) through (D) where is is dangerous to bond and ground a supply-side connected Interconnected Power Production Source like a service. The fault current path to the Utility source though this bonding and grounding makes the installation safer.
 
Status
Not open for further replies.
Top