SER CU Cable comes with 2/0 2/0 2/0 #1?

Status
Not open for further replies.
M

moab88

Member
Location
West Virginia
Occupation
Journeyman Electrician
I'm upgrading a 200 Amp service. From the Weather Head down to the dual meter base I'm running either 400 or 350 kcmill conductors that will parallel to two 200 A meters. Out of those meters I have a disconnect on each side and from those disconnects I'm going to the panel. NEC states I only need 2/0 for my 2 hots and Neutral (Table 310.12). Table 250.66 states that my GEC coming from the disconnects and going into my panel only needs to be #4 AWG. Why when I look up SER cables they list them as 2/0, 2/0, 2/0, #1?
 
The reason the cable comes with a larger 4th wire ,imo, is because the cable could be used as a service cable for 3 phase and thus there isn't an equipment grounding conductor. The #1 would be a neutral.
 
Dennis Alwon said:
The reason the cable comes with a larger 4th wire ,imo, is because the cable could be used as a service cable for 3 phase and thus there isn't an equipment grounding conductor. The #1 would be a neutral.
Click to expand...
This makes sense then, I was getting frustrated because I'm trying to find service cable for a standard split phase 240V house. I'm trying to find the cable that comes with the PVC jacket but individual conductors would be ideal considering I'm running PVC pipe from disconnect to Panel.
 
Why are you running copper?
moab88 said:
Service Cable this is an example of what I've found, but based off Dennis Alwon's reply it seems that this cable is used for 3-phase.
Click to expand...
No, I said that is why they make the equipment grounding conductor larger than needed so that it can work in both situations. If you are piping it why are you putting a cable inside the raceway. Have you priced copper? You are nuts to go with copper. Aluminum is just fine today as it is a different alloy then they used years ago.
 
moab88 said:
standard split phase 240V house.
Click to expand...
moab88 said:
I'm upgrading a 200 Amp service. From the Weather Head down to the dual meter base I'm running either 400 or 350 kcmill conductors that will parallel to two 200 A meters. Out of those meters I have a disconnect on each side and from those disconnects I'm going to the panel. NEC states I only need 2/0 for my 2 hots and Neutral (Table 310.12).
Click to expand...
So, you can only use Table 310.12 after the split where a meter is serving the the entire load of a single dwelling unit. If the loads of a single dwelling unit are split between the two meters, then you can't use Table 310.12 at all. If one meter is supplying all of one dwelling unit, and the other meter is supplying something else (say a workshop in an outbuilding), then you can only use Table 310.12 for the meter that is supplying the dwelling unit. If you have a duplex house with one meter for each dwelling unit, then you could use Table 310.12 for both meters.

Cheers, Wayne
 
wwhitney said:
So, you can only use Table 310.12 after the split where a meter is serving the the entire load of a single dwelling unit. If the loads of a single dwelling unit are split between the two meters, then you can't use Table 310.12 at all. If one meter is supplying all of one dwelling unit, and the other meter is supplying something else (say a workshop in an outbuilding), then you can only use Table 310.12 for the meter that is supplying the dwelling unit. If you have a duplex house with one meter for each dwelling unit, then you could use Table 310.12 for both meters.

Cheers, Wayne
Click to expand...

Unfortunately many inspectors either don't know this or think is is dumb not to allow it. I have argued that here in my own state which tends to allow it.

If he is truly paralleling then 400 amps only needs 332 amps at 83% and 2/0 copper is good for 175 amps - doubled it is 350 amps. I don't think this is what he is doing. It appears he has 2 meters and 2 risers.... Is that correct?

So if there are 2 meters that may change things....
 
Dennis Alwon said:
Unfortunately many inspectors either don't know this or think is is dumb not to allow it. I have argued that here in my own state which tends to allow it.

If he is truly paralleling then 400 amps only needs 332 amps at 83% and 2/0 copper is good for 175 amps - doubled it is 350 amps. I don't think this is what he is doing. It appears he has 2 meters and 2 risers.... Is that correct?

So if there are 2 meters that may change things....
Click to expand...
I have one riser going into a dual meter base. One meter located on the left feeds into a disconnect which feeds the bottom apartment. The other meter located on the right feeds into a disconnect which feeds the top apartment. I was told the "paralleling" takes place where the conductors in my riser reach the meter base. Inside where the riser connects to my meter there are busbars that extend out to each meter. One thing to note, the dual meter base I'm looking at says it can only take at a maximum 350 Kcmill conductor, but both meters are rated for 200A each.
Dennis Alwon said:
Why are you running copper?

No, I said that is why they make the equipment grounding conductor larger than needed so that it can work in both situations. If you are piping it why are you putting a cable inside the raceway. Have you priced copper? You are nuts to go with copper. Aluminum is just fine today as it is a different alloy then they used years ago.
Click to expand...
I understand now thank you for clearing that up for me. I went with copper simply because every job I've worked on used copper and this is my first service upgrade on my own. I felt more comfortable using copper because I'm unaware of any extra steps I would need to take using Aluminum (Ox-Guard, combining copper ground rods and aluminum GEC) I didn't want to take any chances.
wwhitney said:
So, you can only use Table 310.12 after the split where a meter is serving the the entire load of a single dwelling unit. If the loads of a single dwelling unit are split between the two meters, then you can't use Table 310.12 at all. If one meter is supplying all of one dwelling unit, and the other meter is supplying something else (say a workshop in an outbuilding), then you can only use Table 310.12 for the meter that is supplying the dwelling unit. If you have a duplex house with one meter for each dwelling unit, then you could use Table 310.12 for both meters.

Cheers, Wayne
Click to expand...
I have 1 riser and 2 separate meters with disconnects. I did my load calculations but the homeowner is very difficult when it comes to what type of equipment he wants to put in the units. The top unit is going to have a Gas Furnace. Even then he explains how he wants baseboard heaters and is unsure about what type of range and other appliances is going to be in there. He's not even sure if he's going to supply a washer and dryer for this unit. The bottom unit is going to be mainly electric. He has a mini split and talks about how he wants baseboard heating as well and a washer and dryer. He's very inconsistent with information I need for my load calculations and at the same time he went ahead and bought a 200 A panel. The bottom apartment already had a 200 A panel. I figured I could use the wire in the riser as one of the feeds coming from the disconnect to the panel. At the end of the day I knew 200 A for each unit would be sufficient because every possible load calc I did only came up with ~125A at most for the bottom apartment.
 
If you could do a load calculation then the riser only needs to be as large as the calculated load. If you want a true 400 amps then you will have to get a double lug kit for the line side of the meter if it doesn't have it already
 
Dennis Alwon said:
If you could do a load calculation then the riser only needs to be as large as the calculated load. If you want a true 400 amps then you will have to get a double lug kit for the line side of the meter if it doesn't have it already
Click to expand...
I wish I could do a load calculation. I'm sure once I show the homeowner the price of all the materials I've gathered so far he'll be more concerned about giving me the ratings of all his devices in the apartment.

Dual Meter Base here's an example of the type of meter base I'm looking into. Would I be safe just running 350 kcmill with 200 Amp disconnects and 200 amp panels still?
 
Status
Not open for further replies.
Top