LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Hey, all y'all! (That's plural for y'all.)
I have a 2-gang meter, each feeding an upstairs apartment in a mixed-use building. I calculate a 155a demand for each, with 69a on the neutral.
1a. Do I need 350mcm copper (310a @75 deg), or can I use 300mcm copper (320a @90 deg), or can I combine the two loads and re-calculate to a lesser total demand?
1b. Also, can I really take the neutral all the way to #1 (150a @ 90 deg), or must I use #1/0 (150a @75 deg)
1c. It looks like I'll need 2.5" conduit unless I can make the shared entrance conductors smaller than my above calculations, right?
2. There will be two 3R 200a disco's beneath the 2-gang meter base for tenant access. Since we're not allowed to land any grounding conductors in the meter, I have to land them in the disco's.
If the water pipe is near the service, I can use either a single #2 conductor with taps, or a separate #4 cu for each, right?
3. The downstairs retail space will have its own 200a service (separate service entrance due to high-leg for existing 3ph AC unit) sharing the same service drop, separate weatherhead and entrance.
This service's disco will be in its panel, inside the building (back-to-back with the separate 3ph meter), which does not require grouping due to differing characteristics. Is it permissable to run a single, unbroken #6 from disco to disco to disco and then to the driven grounds?
Here's a click-to-enlarge drawing illustrating this installation:
I have a 2-gang meter, each feeding an upstairs apartment in a mixed-use building. I calculate a 155a demand for each, with 69a on the neutral.
1a. Do I need 350mcm copper (310a @75 deg), or can I use 300mcm copper (320a @90 deg), or can I combine the two loads and re-calculate to a lesser total demand?
1b. Also, can I really take the neutral all the way to #1 (150a @ 90 deg), or must I use #1/0 (150a @75 deg)
1c. It looks like I'll need 2.5" conduit unless I can make the shared entrance conductors smaller than my above calculations, right?
2. There will be two 3R 200a disco's beneath the 2-gang meter base for tenant access. Since we're not allowed to land any grounding conductors in the meter, I have to land them in the disco's.
If the water pipe is near the service, I can use either a single #2 conductor with taps, or a separate #4 cu for each, right?
3. The downstairs retail space will have its own 200a service (separate service entrance due to high-leg for existing 3ph AC unit) sharing the same service drop, separate weatherhead and entrance.
This service's disco will be in its panel, inside the building (back-to-back with the separate 3ph meter), which does not require grouping due to differing characteristics. Is it permissable to run a single, unbroken #6 from disco to disco to disco and then to the driven grounds?
Here's a click-to-enlarge drawing illustrating this installation: