# 350 amp service drop conductors



## ikeberg9 (Jan 8, 2010)

I'm doing a 350A service(existing 200A panel and a new 150A panel) and it's overhead service drop. I don't do as much residential and the only heavy up's I've done are 200 amp and a couple underground 600A. So my question to most of you residential guys that do this everyday, what do yal use or would you use for a 350 amp service drop down to your meter. A 500 kcmil SE is a special order item at the supply houses, so would you use that or can you parallel two 1/0 SE's, or should I just call the poco and see what they prefer.


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## jwjrw (Jan 14, 2010)

Just because you have a 200 and a 150 amp panel that does not make it a 350A service. You should do a load calc to see what size conductors you need....Could you not just make the new panel a sub panel? Or do you need to increase the service size due to loads being added?


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## ikeberg9 (Jan 8, 2010)

Ya, but it's a separate 150 amp panel that isn't coming off the 200 amp panel so the wire should be protected up to 350 since there is the potential to draw 350 amps on that wire. When you do a 200 amp service even if you know it will never see 200 amps you still size the service drop to 4/0 AL or 2/0 CU, right?


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## ikeberg9 (Jan 8, 2010)

I need to increase the load, because it cost way too much to get gas back in the addition, so everything is electric(stove, heat, etc.). The existing 200 amp panel would be cutting it too close, so we went ahead and throwing in a new panel.


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## jwjrw (Jan 14, 2010)

ikeberg9 said:


> Ya, but it's a separate 150 amp panel that isn't coming off the 200 amp panel so the wire should be protected up to 350 since there is the potential to draw 350 amps on that wire. When you do a 200 amp service even if you know it will never see 200 amps you still size the service drop to 4/0 AL or 2/0 CU, right?




Then run a conduit riser and 350 copper single conductor or 500 aluminum.
Do you actually need to increase the service size due to loads being added?


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## ikeberg9 (Jan 8, 2010)

Ya, because like I said it was too much for the existing 200, and I could have done 100 amp but it was close enough after calculations and it's not much more for the extra 50 amps. I was trying to avoid pipe because the meter will be around the corner, so because of location I will have to do bends and an lb which I think will look tacky compared to SE. If I did do pipe how does that work anyway. Is there a special way to seal of the the top of the pipe since it's running straight down into the top of the meter. Never done pipe or seen pipe used for the overhead.


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## randas (Dec 14, 2008)

ikeberg9 said:


> If I did do pipe how does that work anyway. Is there a special way to seal of the the top of the pipe since it's running straight down into the top of the meter. Never done pipe or seen pipe used for the overhead.


:001_huh:

3M 33 DUH


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## jwjrw (Jan 14, 2010)

Are you sure you are qualified to do this work? :huh:


Meter Hub
Rigid Pipe, or Pvc pipe and connector, or emt and weatherproof connector
Conduit
Weatherhead


You really have never seen an overhead riser in conduit? Most people have never seen a SEU one.


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## ikeberg9 (Jan 8, 2010)

Wow, I knew someone would ask if I was qualified. Ya, well I'm sure I have seen it in pipe but I didn't pay close enough attention to it, and a lot of houses around here are underground and all overheads I've done were se cable. Like I said I do mostly commercial like 90% commercial. I do switchgears and stuff, rarely residential. That's why I was trying to find out how you residence guys do it. I wasn't aware of connectors for the pipe to weatherproof, never seen one, and a bunch of 3m rubber isn't the way I wanna seal off a pipe.


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## jwjrw (Jan 14, 2010)

ikeberg9 said:


> Wow, I knew someone would ask if I was qualified. Ya, well I'm sure I have seen it in pipe but I didn't pay close enough attention to it, and a lot of houses around here are underground and all overheads I've done were se cable. Like I said I do mostly commercial like 90% commercial. I do switchgears and stuff, rarely residential. That's why I was trying to find out how you residence guys do it. I wasn't aware of connectors for the pipe to weatherproof, never seen one, and a bunch of 3m rubber isn't the way I wanna seal off a pipe.



I do commercial and residential. In my area you see both SE and conduit risers as well as underground. I see very few commercial buildings with anything but conduit. That said I have never heard of an electrician who didn't know how to install a conduit riser. Maybe things are done differently where you are. No disrespect meant. It just seems like something even a green apprentice would know here.


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## Dennis Alwon (May 9, 2009)

If the service goes thru the roof it is a riser and you need galvinized rigid conduit, etc. If it just goes up the side of the building then it only needs PVC or service entrance cable. 

The riser/mast wires only need to be sized to the calculated load. You can use larger wire if you want.


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## ikeberg9 (Jan 8, 2010)

I understand where your coming from, I just really have never had to do a pipe riser where the wire just comes out at the top for the service and wasn't sure how it was sealed of professionally, not just with tape and duct seal. Like I said before, all the residential overheads I've done were all SE cable or ther service was underground. It's not that I don't know how to do a riser, just never have and was curious how it's sealed off. Most of us electricians, regardless of how long you've been doing it, run into things that you have never had to do before or seen done, and even though you can figure it yourself and for the most part know what's going on, when you have a forum like this for professionals, which all of us deal with certain aspects of the electrical field on a regular basis that other electricians have not had to deal with, it's nice to find out how they go about the situation.


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## Dennis Alwon (May 9, 2009)

Here you go


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## Magnettica (Jan 23, 2007)

Are conductor ampacities different in commercial? :laughing:


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## ikeberg9 (Jan 8, 2010)

Thanks for the pics Dennis. 

Who's talking about ampacity magnettica, were talking about sealing off pipe risers.


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## backstay (Feb 3, 2011)

What is the 150 amp panel for? Just more load for the house or something else like heat? I've never had to go bigger than 200 for the house service, even in 3500 to 4000 sq/ft houses. I've had to add sub panels to get more breakers, or an extra service for heating(electric storage). If i was adding a panel it would be 200 amps not 150, cheaper a 40 ckt 200 amp Siemens is $130 a 30 ckt 150 is $150.


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## ikeberg9 (Jan 8, 2010)

Your right, 200 amp panel is cheaper since it is more common, but wire isn't. It's a 70' from the panel back to the meter. None of the house has gas and they don't have oil, so the existing house which is pretty big has electric heat, electric stove, a barn with a(if I remember correctly) 80 amp sub-panel(which has a welder, air compressor, and power tools). The new addition has electric heat, electric stove, and there planning on putting in a garage later so there gonna need power out there too.


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