Downsizing Neutral OK??

[Mikemayo]

Here's one for you. It's been my belief that down sizing a neutral was a thing of the past, and I can't remember the last time I've done it. For services or for anything else. But after some tantalizing conversations I'm now questioning if this is something I've rationalized as being "against code" simply because I don't do it myself. Is one allowed to downsize a neutral? And what circumstances allow for it? I believe the utility side of a service I've seen downsized but what about from load side of meter to panel?
Looking forward to my eyes being opened

 

[bkludecke]

220.61

 

[don_resqcapt19]

Where the line to neutral loads are very small, you also have to look to 250.24(C). The minimum size is the larger of what is required by 220.61 or 250.24(C).

 

[ggunn]

Here's one for you. It's been my belief that down sizing a neutral was a thing of the past, and I can't remember the last time I've done it. For services or for anything else. But after some tantalizing conversations I'm now questioning if this is something I've rationalized as being "against code" simply because I don't do it myself. Is one allowed to downsize a neutral? And what circumstances allow for it? I believe the utility side of a service I've seen downsized but what about from load side of meter to panel?
Looking forward to my eyes being opened

One situation where you can reduce the neutral to the size of the EGC is when the conductors are a PV inverter output circuit and the inverter(s) use the neutral only for instrumentation and voltage reference.

 

[jeff48356]

Here's one for you. It's been my belief that down sizing a neutral was a thing of the past, and I can't remember the last time I've done it. For services or for anything else. But after some tantalizing conversations I'm now questioning if this is something I've rationalized as being "against code" simply because I don't do it myself. Is one allowed to downsize a neutral? And what circumstances allow for it? I believe the utility side of a service I've seen downsized but what about from load side of meter to panel?
Looking forward to my eyes being opened

Sure, I do that whenever I install a service. For a 200A service, we use aluminum 4/0 for hots and 2/0 for neutral. For copper, it's 2/0 for hots and 1/0 for neutral.

 

[Mikemayo]

Sure, I do that whenever I install a service. For a 200A service, we use aluminum 4/0 for hots and 2/0 for neutral. For copper, it's 2/0 for hots and 1/0 for neutral.

Now what are the specifics of the code for that? What I'm wondering is if it's allowed for the service, if you have a meter with its own breaker wouldyou or could you run a down sized neutral from the meter to the panel? Do you only down size above the meter?

 

[ActionDave]

Now what are the specifics of the code for that? What I'm wondering is if it's allowed for the service, if you have a meter with its own breaker wouldyou or could you run a down sized neutral from the meter to the panel? Do you only down size above the meter?

You can do both. Most of the time I will down size a neutral one or two sizes for a service. I know there are data centers and the Like that need special considerations, but for most installs that doesn't exist.