With a line-side tap should the neutral continue on to the MSP?

Status
Not open for further replies.
P

photonboy

Member
Location
Berkeley, CA, USA
Occupation
Ex roof monkey, current desk jockey
For a while I was calling it out when installers were bonding the neutral to the EGC in fused AC discos for taps but now that the code requires it I'm ok with that, now I'm seeing some installers terminating the (bonded) neutral in the AC disco rather than having it continue to the MSP. Is that legit? What's going on electrically with that?
 

Attachments

  • IMG_2850.jpg
    IMG_2850.jpg
    347.3 KB · Views: 35
photonboy said:
now I'm seeing some installers terminating the (bonded) neutral in the AC disco rather than having it continue to the MSP. Is that legit? What's going on electrically with that?
Click to expand...
What MSP? If the line-side PV connection is treated as a second service entrance, then the fused AC disco is the associated service disconnect/OCPD. So any downstream panel for the PV system would not be a service panel. If the PV system doesn't require a neutral conductor, then the neutral doesn't have to run any farther than this service disconnect.

Cheers, Wayne
 
That green bonding screw shouldn't be installed unless it's a supply side tap for the PV.

If this disconnect is on the load side of the MSP main breaker there is a chance nuetral current could flow on the EGC.

Sent from my SM-G998U using Tapatalk
 
photonboy said:
For a while I was calling it out when installers were bonding the neutral to the EGC in fused AC discos for taps but now that the code requires it I'm ok with that, now I'm seeing some installers terminating the (bonded) neutral in the AC disco rather than having it continue to the MSP. Is that legit? What's going on electrically with that?
Click to expand...
We need to get clear on your terms. If you are talking about a line side tap (that just happens to be in the MSP on the line side of the main as opposed to connecting at a point further upstream) the the neutral must be brought to the tap disconnecting means and bonded with a main bonding jumper (regardless of whether the invertor requires a neutral).
If you are referring to a load side tap, that is another discussion.
 
photonboy said:
For a while I was calling it out when installers were bonding the neutral to the EGC in fused AC discos for taps but now that the code requires it I'm ok with that, now I'm seeing some installers terminating the (bonded) neutral in the AC disco rather than having it continue to the MSP. Is that legit? What's going on electrically with that?
Click to expand...
Your picture is obviously of an incomplete install and like others I'm a bit confused by the lack of a complete description.

If the solar system requires a neutral then that neutral needs to go all the way to the equipment back from wherever the ungrounded conductors are tapped for the line side tap. (Tap being a colloquial term here; technically you're branching off service entrance conductors or a PV feeder.) It also gets bonded in the disco, and a green wire between the tap and the PV disco is not necessary.

If the system does not require a neutral then it's the same except that the neutral does not need to continue from the PV disco to the PV equipment.

If you're photo shows the PV system side installed and the utility side waiting to be completed, then the completion must include a neutral. If the photo shows the utility side completed, then the ungrounded conductors are done in error; they should be landed on the line terminals at the top of the disco.
 
jaggedben said:
He said line-side tap in the subject line.
Click to expand...
I was thinking maybe there was confusion on what a line side tap was vs. load side. The majority of inspectors I work with, I have to explain that difference.

Sent from my SM-G998U using Tapatalk
 
photonboy said:
Wasn't the best pic for my example, was from a job not completed yet. Question is still valid though, does the neutral have to continue to the MSP in the case of a line-side tap?
Click to expand...
Wayne answered this in post #2. The neutral has to go from the point of interconnection as far as the PV AC disconnect, but if there isn't anything past it that requires a neutral, then it can stop there.
 
Status
Not open for further replies.
Top