Revision as of 01:57, 16 September 2023

NEC 690 - Covers PV Systems

690.41 - Equipment Grounding Conductor requirements [1]
- 690.41(B) also requires ground fault protection except if there are no more than 2 strings (PV source circuits [2])
  - Since NEC 2020, ground fault indicator must be readily visible (but not necessarily readily accessible?) [3]
- 690.45 - size of PV equipment grounding conductors - Table 250.122 + no less than 14 ga.
690.9(A) says that we don't need overcurrent device for PV if the wires can handle short current capacity of PV. But good luck trying to convince a code official.
PV Grounding PDF [4]. Although the NEC does not specifically require all equipment to be certified/listed, many local jurisdictions and many AHJs establish requirements that all equipment be certified/listed because they feel unqualified to examine uncertified/unlisted equipment for safety as the NEC requires.
- Good overview doc. Read it from p. 6 on to understand equipment ground, system ground.
- Additional issue for PV is that in cloudy conditions, if you get a fault, a breaker may not trip because current is too low. For this reason, extra ground fault protection devices may be required.
Is earth ground of a PV system connected to DC negative, or to AC neutral?

Article says that a common ground fault protection device (GFPD) is a fuse to ground - [5]
NEC Article 690.41

Solar PV standards and certifications - [6]. Class II means frames grounded, no system ground.

Paper on PV grounding, 1984. Fire safety and personnel safety are typically tradeoffs? [7]
- Solidly grounded means neutral is connected to earth electrode. [8]
- Class II system had double insulation and equipment ground, but no earth connection.
- Class I has equipment ground and earth connection.
- Insulation failures between current-carrying conductors and the ground are known as ground faults.
Classic video by Mike Holt. Equipment Grounding + system grounding - Ground and grounding electrode conductor basic with Mike Holt - [9]
- Do not earth ground frames with a ground rod like this - [10]

PV panels should follow electrical grounding conductor sizes - [11]
Ie, for 30A DC, we need 10 ga ground.
PV frames must be connected to PV system equipment grounding conductor [12]
After leaving the PV array, the equipment ground must run together with the power wires. [13]

Australia rules - appear to say 6 ga for lightning protection, and 12 ga for frame grounding [14]
6 ga USA if 'subject to damage'?

@@ Line 1: / Line 1: @@
 =NEC 690 - Covers PV Systems=
-*690.41 - Equipment Grounding Conductor requirements [https://codes.iccsafe.org/content/ISEP2018/national-electrical-code-nec-solar-provisions#ISEP2018_NEC_Sec690.41]
+*'''690.41''' - Equipment Grounding Conductor requirements [https://codes.iccsafe.org/content/ISEP2018/national-electrical-code-nec-solar-provisions#ISEP2018_NEC_Sec690.41]
 **'''690.41(B) also requires ground fault protection''' except if there are no more than 2 strings (PV source circuits [https://www.e-education.psu.edu/ae868/node/965#:~:text=A%20PV%20source%20circuit%20is,usually%20only%20one%20source%20circuit.])
 ***Since NEC 2020, ground fault indicator must be readily visible (but not necessarily readily accessible?) [http://www.codebookcity.com/codearticles/nec/necarticle690-5.htm]
@@ Line 9: / Line 9: @@
 **Additional issue for PV is that in cloudy conditions, if you get a fault, a breaker may not trip because current is too low. For this reason, extra ground fault protection devices may be required.
 *'''Is earth ground of a PV system connected to DC negative, or to AC neutral?
+=Ground Faults - System Grounding Howto=
+*Article says that a common ground fault protection device (GFPD) is a fuse to ground - [https://ep-us.mersen.com/sites/mersen_us/files/2018-11/TT-PVPN1-Ground-Fault-Analysis-and-Protection-in-PV-Arrays-Tech-Topic.pdf]
+*'''NEC Article 690.41'''
 =More=