2-2-4 SER

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U

upstatecontractor

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In the past we have always run 2-2-4 SER aluminum for 100 amp generators, I am being told we can no longer do this< generator is rated at 100 amp (20KW) 10/240 volts< is this correct? what would be the allowable amperage for this?
 
Dennis Alwon

Dennis Alwon

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Chapel Hill, NC
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It depends on the code cycle and whether it carries the entire load of the service. If it does not carry the entire load then T. 310.16 comes into play and then depending if the wire is run thru insulation it may be rated at 60C which is 75 amps or possibly 75C- 90 amps.
 
U

upstatecontractor

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feed

feed

yes Im sorry, the feed from generator is 2-2-4 only fron transfwe switch to panel is 4/0 al. also where does it say i need to seperate grounds and neutrals in main panel
 
kwired

kwired

Electron manager
Location
NE Nebraska
upstatecontractor said:
yes Im sorry, the feed from generator is 2-2-4 only fron transfwe switch to panel is 4/0 al. also where does it say i need to seperate grounds and neutrals in main panel
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What do you mean by main panel? If the panel contains the service disconnect, grounds and neutrals do not need separated. Anything on load side of service disconnect they do need separated. 250.24(A)(5) 2008 NEC.

The panel you described is not service equipment, the transfer switch is. Neutrals and grounds must be separated past the transfer switch in this installation.
 
ceb58

ceb58

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Raeford, NC
kwired said:
What do you mean by main panel? If the panel contains the service disconnect, grounds and neutrals do not need separated. Anything on load side of service disconnect they do need separated. 250.24(A)(5) 2008 NEC.

The panel you described is not service equipment, the transfer switch is. Neutrals and grounds must be separated past the transfer switch in this installation.
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Very much agree. What about your load calculation? Is it less than 83 amps or are you load sheding? And I hope you are using 4 wire ser and not 3 wire se from the gen.
 
stickboy1375

stickboy1375

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Location
Litchfield, CT
ceb58 said:
Yes, and the OP stated dont see but 3 numbers there.
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Good point, i've always taken this for granted, if I called up an ordered 4/0 SER, they would automatically send me 3 conductors and a bare ground, if I ordered 4/0 SEU, they would send me 2 conductors with a concentric ground...
 
H

hurk27

Senior Member
Location
Portage, Indiana NEC: 2008
upstatecontractor said:
yes Im sorry, the feed from generator is 2-2-4 only fron transfwe switch to panel is 4/0 al. also where does it say i need to seperate grounds and neutrals in main panel
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Since you are transferring the whole service, you are required to use a service rated transfer switch, in this requirement this transfer switch will have a 200 amp main service disconnect/breaker, so you have now moved your service point from the existing main breaker panel to this transfer switch and need to treat it as the service disconnect, this makes the conductors feeding the existing panel feeders, and thus you will have to up date this panel as a sub panel and it will require having the neutral and grounds to be un-bonded and or seperated as well as a 4-wire feed to this panel, also any grounding electrode conductors will be require to be moved to the transfer switch as they are not allowed in the now made sub panel.

Ya I know "OUCH"
 
stickboy1375

stickboy1375

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Litchfield, CT
hurk27 said:
Since you are transferring the whole service, you are required to use a service rated transfer switch, in this requirement this transfer switch will have a 200 amp main service disconnect/breaker,
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Couldn't I just use a 200 amp service rated disconnect with main breaker, then a 200 amp transfer switch? or if I prefer, your method....
 
Little Bill

Little Bill

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Tennessee NEC:2017
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Semi-Retired Electrician
Smart $ said:
See the Southwire spec chart that I linked to in my earlier post. They make both 2-2-4 SER and 2-2-4 SEU.
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I was only stating what the terminology used here was. Also note in the link they say formally referred to as 3 conductor, 4 conductor, etc. Sounds like they changed their terminology.
 
H

hurk27

Senior Member
Location
Portage, Indiana NEC: 2008
stickboy1375 said:
Couldn't I just use a 200 amp service rated disconnect with main breaker, then a 200 amp transfer switch? or if I prefer, your method....
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Sure and is done all the time but even though, you are still moving the service point to this disconnect, everything else still applies, anytime I order a ATS when doing this kind of install I make sure I get a service rated ATS with a main breaker, much cheaper then a separate 200 amp disconnect with breaker and less work.
 
kwired

kwired

Electron manager
Location
NE Nebraska
hurk27 said:
Sure and is done all the time but even though, you are still moving the service point to this disconnect, everything else still applies, anytime I order a ATS when doing this kind of install I make sure I get a service rated ATS with a main breaker, much cheaper then a separate 200 amp disconnect with breaker and less work.
Click to expand...

Can also be a big advantage if you are starving for space to install everything.
 
U

upstatecontractor

Member
major confusion

major confusion

HELP!! after speaking with the local inspector, he states that #2 SER (4 wire) is sufficient size to run from the generator to the transfer switch. He stated that table 310.15 (B) (6) was able to be used because the feeder from the generator to the transfer switch on a power outage becomes the "main power feeder" which allows #2 aluminum to cary the 100 amp load from the generator> Please help!! i am so confused now
 
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