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HPWC SER vs Romex Wire?
- Thread starter SureValla
- Start date
Reddy Kilowatt
Active Member
Article 338 says to stick with the 60c-140C chart on SER. I can't tell what the insulation is on the Lowe's cable. I don't know why they took the liberty on the 100A vs 90A. I know what article 240 says. can't tell you what to use.
SER is NOT rated for underground wiring in any way. USE is for underground. I don't know what your route is, underground, overhead. at that point pipe and individual wire would probably be cheaper.
Honestly I'm not sure what I would use between sub panels Romex? still 60C per Article 334. SER is allowed inside under the guidance of 338 and 334.
I think I used a #4 Copper Romex for my 60 Amp charger. I did not use aluminum. I didn't want to go cheap on the charger and it was a long pull. I don't play games with the charts to save a buck. Copper gets real pricey at that 100A level.
SER is NOT rated for underground wiring in any way. USE is for underground. I don't know what your route is, underground, overhead. at that point pipe and individual wire would probably be cheaper.
Honestly I'm not sure what I would use between sub panels Romex? still 60C per Article 334. SER is allowed inside under the guidance of 338 and 334.
I think I used a #4 Copper Romex for my 60 Amp charger. I did not use aluminum. I didn't want to go cheap on the charger and it was a long pull. I don't play games with the charts to save a buck. Copper gets real pricey at that 100A level.
All they make is 90c wire. But i have no idea on earth why an electrician would want to use 2-2 romex...
Conduit is almost always easier to use than running conduit of there is Sheetrock.
I read that SER cannot be used in conduit underground because it is not rated for wet. But this says "wet or dry locations:"
https://www.lowes.com/pd/Southwire-2-2-2-4-Aluminum-Ser-Service-Entrance-Cable-By-the-Foot/4294349
Anyway, I have my plan. 100 amp sub-panel with 3 AWG THHN that goes in 1.25 conduit underground to house, where it is spliced using the proper clamps to SER 2-2-2-5 for the final run to my main panel.
For now, I will stick a 50 amp NEMA onto the sub-panel that will work with my plasma cutter or a car, knowing I can add a Wall Connector later.
I expect it to be done as soon as Saturday. Meanwhile, tomorrow the electrician quote to do this same work will come in, so I can see how much I saved by doing it myself.
https://www.lowes.com/pd/Southwire-2-2-2-4-Aluminum-Ser-Service-Entrance-Cable-By-the-Foot/4294349
Anyway, I have my plan. 100 amp sub-panel with 3 AWG THHN that goes in 1.25 conduit underground to house, where it is spliced using the proper clamps to SER 2-2-2-5 for the final run to my main panel.
For now, I will stick a 50 amp NEMA onto the sub-panel that will work with my plasma cutter or a car, knowing I can add a Wall Connector later.
I expect it to be done as soon as Saturday. Meanwhile, tomorrow the electrician quote to do this same work will come in, so I can see how much I saved by doing it myself.
splicing high current cable, especially by a novice, is asking for a fire.
Direct burial and underground are not the same thing.
SER cable is not recommend to be installed in conduit underground because ground wire will be subject to corrosion because it is not insulated. However, a pipe is wet location and ser is rated for wet locations and therefore it is not necessarily a code violation. It would be up to AHJ to decide, but if it were me i would say no good.
Are you running the cable underground? If not, i would just run SER the entire run.
Direct burial and underground are not the same thing.
SER cable is not recommend to be installed in conduit underground because ground wire will be subject to corrosion because it is not insulated. However, a pipe is wet location and ser is rated for wet locations and therefore it is not necessarily a code violation. It would be up to AHJ to decide, but if it were me i would say no good.
Are you running the cable underground? If not, i would just run SER the entire run.
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i would suggest using these instead.
Polaris Insulated Multitap Connector, 1.84 In. L IT-3/0B | Zoro.com
Polaris Insulated Multitap Connector, 1.84 In. L IT-3/0B | Zoro.com
Electrician was supposed to give me a quote this morning to do this work, but he didn't yet, and I got impatient and so I started doing it myself. I bet it is done by the time he emails me. I expect to finish Monday night as I have a giant junction box coming on Monday for the splice.
My 20 foot trench is mostly done, but hard to get down to 18 inches in a few spots so I am resting until tomorrow.
I ran 50 feet of SER in my basement.
I passed the conduit through my outer wall in two spots.
I cut plaster and put in the sub-panel.
I wired in a box and 14-50 outlet and ran the wire to the sub-panel inside the wall. Pretty hard to work with this wire inside of a box.
My THHN is coming on Sunday so I will pull that then and splice it to the SER.
...And I didn't know that 3/0 was not 3 AWG, so I had three Lowes employees pull down a 500 foot spool and cut 140 feet of it before figuring out it was 200 amp wire several sizes larger than 3. Lowes has this massive stuff on sale for just 75 cents a foot. Good thing I figured it out before I left as I didn't have to pay for it.
One thing I have not figured out is how to get the SER into my main panel. The numbnuts who mounted it has it right beside another panel so there is not really any side access, and the top is full. Maybe there is room under it or maybe I can enlarge one of the smaller holes on the top with a Dremel.
My 20 foot trench is mostly done, but hard to get down to 18 inches in a few spots so I am resting until tomorrow.
I ran 50 feet of SER in my basement.
I passed the conduit through my outer wall in two spots.
I cut plaster and put in the sub-panel.
I wired in a box and 14-50 outlet and ran the wire to the sub-panel inside the wall. Pretty hard to work with this wire inside of a box.
My THHN is coming on Sunday so I will pull that then and splice it to the SER.
...And I didn't know that 3/0 was not 3 AWG, so I had three Lowes employees pull down a 500 foot spool and cut 140 feet of it before figuring out it was 200 amp wire several sizes larger than 3. Lowes has this massive stuff on sale for just 75 cents a foot. Good thing I figured it out before I left as I didn't have to pay for it.
One thing I have not figured out is how to get the SER into my main panel. The numbnuts who mounted it has it right beside another panel so there is not really any side access, and the top is full. Maybe there is room under it or maybe I can enlarge one of the smaller holes on the top with a Dremel.
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You shouldn’t use a dremel, you should use a hole punch. Did you use connectors for the wires entering the box? Also, did you isolate the grounds and neutrals in the sub panel?
The top of the conduit needs to be at 18”, so if you got 1.5” conduit you need to dig down to 20”. Personally, i just run IMC metallic conduit and in that instance you only need to be down 8”....
This is a hole punch kit:
https://www.amazon.com/gp/slredirec...6330735&id=3491875835539339&widgetName=sp_atf
But you can possibly rent on from sunbelt or homedepot.
The top of the conduit needs to be at 18”, so if you got 1.5” conduit you need to dig down to 20”. Personally, i just run IMC metallic conduit and in that instance you only need to be down 8”....
This is a hole punch kit:
https://www.amazon.com/gp/slredirec...6330735&id=3491875835539339&widgetName=sp_atf
But you can possibly rent on from sunbelt or homedepot.
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A possible snag.
My Square D by Schneider Electric HOM612L100SCP Homeline 100 Amp 6-Space 12-Circuit panel says on the label that the max branch breaker is 70 amps.
Their website FAQ uses different language and speaks of 70 amps as the "largest single pole" breaker.
I can't call them on the weekend, and I don't want to install this if I can't use a 100 amp double-pole breaker.
My Square D by Schneider Electric HOM612L100SCP Homeline 100 Amp 6-Space 12-Circuit panel says on the label that the max branch breaker is 70 amps.
Their website FAQ uses different language and speaks of 70 amps as the "largest single pole" breaker.
I can't call them on the weekend, and I don't want to install this if I can't use a 100 amp double-pole breaker.
I am using clamps for the wires entering the box. Not sure if that is what you mean by connectors, but I am not leaving them bare if that is what you are asking.
The ground comes isolated on this panel, but yes, it will be kept isolated. Also for that matter, I need a ground bar kit which the Amazon listing for this panel incorrectly states is to be used when the panel is for service entrance use.
Thanks for the conduit tip.
The ground comes isolated on this panel, but yes, it will be kept isolated. Also for that matter, I need a ground bar kit which the Amazon listing for this panel incorrectly states is to be used when the panel is for service entrance use.
Thanks for the conduit tip.
Agree. Code requires a disconnect, and you can’t use aluminum wire for direct connections to the HPWC.
I am sad. Even though basically every electrician uses a 100 amp breaker for 2-2-2-4 SER cable to a sub-panel (that is how my existing sub-panels are wired), the NEC makes you use the 75C ampacity column. So, that means you are supposed to use a 90 amp breaker. I had my heart set on 100 amps. For me to change the wire now would cost me about $220 more for new wire, and require conduit in my unfinished basement ceiling which is really crowded around ducts and light fixtures and stuff, and would be a bunch more work to install. The crowded-to-navigate ceiling is
There is no real benefit to 100 amps as Tesla only charges at a max using a 60 amp breaker (48 amps), and they once in the past sold a Model-X with an option to use a 90 amp breaker (72 amps), but got rid of that option. So it seems like for the future they are sticking to 60 amp breakers max. Maybe they will go to 90 some day again when the Cyber Truck comes out, but probably never 100. So I should not care, but I feel like my attempt to install 100 amps was foiled.
I should probably stick to the 90 now, and if I ever wanted to change to 100, it is not really any harder to do it again later since I have 3 AWG copper into the basement already where the main panel is. I just feel defeated by this NEC table entry.
There is no real benefit to 100 amps as Tesla only charges at a max using a 60 amp breaker (48 amps), and they once in the past sold a Model-X with an option to use a 90 amp breaker (72 amps), but got rid of that option. So it seems like for the future they are sticking to 60 amp breakers max. Maybe they will go to 90 some day again when the Cyber Truck comes out, but probably never 100. So I should not care, but I feel like my attempt to install 100 amps was foiled.
I should probably stick to the 90 now, and if I ever wanted to change to 100, it is not really any harder to do it again later since I have 3 AWG copper into the basement already where the main panel is. I just feel defeated by this NEC table entry.
And even then, my "100 amp" sub-panel has a label on it saying a branch circuit cannot be more than 70 amp breaker.
So in order to do a 90 amp breaker, I would need to replace the sub-panel with a dedicated cutoff such as a "Square D by Schneider Electric D223N 100-Amp 240-Volt Two-Pole Indoor General Duty Fusible Safety Switch with Neutral." And in order to do a 100 amp breaker, I would need both that and also replace the AL SER 2-2-2-4 with 3 THHN.
So yeah, I am capped at 70A final breaker and 56 charging amps max (yes, I know no current car does more than 48).
So in order to do a 90 amp breaker, I would need to replace the sub-panel with a dedicated cutoff such as a "Square D by Schneider Electric D223N 100-Amp 240-Volt Two-Pole Indoor General Duty Fusible Safety Switch with Neutral." And in order to do a 100 amp breaker, I would need both that and also replace the AL SER 2-2-2-4 with 3 THHN.
So yeah, I am capped at 70A final breaker and 56 charging amps max (yes, I know no current car does more than 48).
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