# 90 volts



## chris.b (Jan 28, 2013)

I went to look at a panel that customer said had 90 volts to all circuits that were on the breakers installed on the left side of the panel but had 122 volts to the breakers on the right. As it turned out he was right, but only if you read it from the breakers on the left to the neutral bar on the left. If you read it from each phase to the neutral bar on the right, it read around 122 on both phases, 90 on the left. 122 to ground. This was a Cutler Hammer BR main lug panel.

This house is over 6 years old, and has not had any problem until now. New owner has been in this house for a month. The appliances came with the house. But, she decided to buy new appliances and that is when she started having problems. 

Outside there is underground service to the meter and 200 amp disconnect. 2/0 Al SER feeds the main lug panel in the house. This house passed rough and final inspection and passed the Home Inspection. 

Anyone know what was wrong and how it worked for so long?


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## joebanana (Dec 21, 2010)

Did you pull the meter, and check from the stabs to the neuch?


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## chris.b (Jan 28, 2013)

No need. It was good to the right side.


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## joebanana (Dec 21, 2010)

What I'm getting at, is the POCO could have lost the ground @ the xfmr.


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## chris.b (Jan 28, 2013)

How is it good on the right but not the left?


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## joebanana (Dec 21, 2010)

You do understand how 120/240 works, right? Does 122v. sound right?


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## chris.b (Jan 28, 2013)

It doesn't sound bad. 245 volts across the phases. Does 90 sound right?


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## Jay82304 (May 12, 2015)

The 2 neautral bars generally have a wire or bar connecting them together. Is there a loose connection on that wire/bar?


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## chris.b (Jan 28, 2013)

DING DING DING!!!! It had NOTHING tying them together!!! 

Now how did work for so long?


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## joebanana (Dec 21, 2010)

Did you do a complete panel inspection?


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## backstay (Feb 3, 2011)

120/240 1ph service has two hits and a neutral, not two phases. Is MLO panel 200 amp? 2/0 is no good for that. Check power with all breakers open, then with a heavy load on one ht then the other. If only one hot drops voltage, it has a hot going. If both change, one going up and one going down, you have a neutral problem.


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## chris.b (Jan 28, 2013)

backstay said:


> 120/240 1ph service has two hits and a neutral, not two phases. Is MLO panel 200 amp? 2/0 is no good for that. Check power with all breakers open, then with a heavy load on one ht then the other. If only one hot drops voltage, it has a hot going. If both change, one going up and one going down, you have a neutral problem.


I knew someone would say something about the "phases". But that is ok. You caught that, but you missed the 200 amp Disconnect part. The panel rating doesn't matter to the wire size in this situation. It could be a 225 amp and wouldn't matter. Worse if it was 125.

I gave you all the information. Read it again.


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## Mich drew (Mar 3, 2013)

chris.b said:


> DING DING DING!!!! It had NOTHING tying them together!!!
> 
> Now how did work for so long?


Is there a disconnect outside? If there is, the neutral bar has to be isolated at the panel, bonded in the disconnect. Maybe someone took out the jumper between the two bars in the panel so neuts and grounds could be separated . Are there neuts and ground on both bars?


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## chris.b (Jan 28, 2013)

Mich drew said:


> Is there a disconnect outside? If there is, the neutral bar has to be isolated at the panel, bonded in the disconnect. Maybe someone took out the jumper between the two bars in the panel so neuts and grounds could be separated . Are there neuts and ground on both bars?


Seperate ground bar with all grounds landed there. No bonding in the panel. Bonded at the disconnect.


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## emtnut (Mar 1, 2015)

chris.b said:


> Seperate ground bar with all grounds landed there. No bonding in the panel. Bonded at the disconnect.


From your post I gather there are 2 neutral bars ... how are they tied together ?


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## chris.b (Jan 28, 2013)

emtnut said:


> From your post I gather there are 2 neutral bars ... how are they tied together ?


They were not.


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## emtnut (Mar 1, 2015)

chris.b said:


> They were not.


That kinda sounds like what the problem is :blink:

They have to be tied together, either through the panel, or a wire


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## chris.b (Jan 28, 2013)

emtnut said:


> That kinda sounds like what the problem is :blink:
> 
> They have to be tied together, either through the panel, or a wire


Exactly, but how did it work for 6 years?


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## emtnut (Mar 1, 2015)

chris.b said:


> Exactly, but how did it work for 6 years?


They must have been connected in some way ....

Something corroded out ?

Load changed to make the problem show up ?

Just guessing, cause I'm not standing in from of the panel


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## chris.b (Jan 28, 2013)

When did the problem show up? After they changed the appliances.


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## emtnut (Mar 1, 2015)

Re-read your post ... the customer got new appliances ...

The old appliances had neutral tied to ground, thereby completing the circuit:thumbup:

**edit*** One neutral bar is actually ground !!!


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## emtnut (Mar 1, 2015)

chris.b said:


> When did the problem show up? After they changed the appliances.


I think we're on to something :thumbsup:


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## Bootss (Dec 30, 2011)

:vs_cry::vs_cry::vs_cry:

comprehensive voltage check of panel and meterms jaws,visual inspection,continuity check with no power,you may want to pull all the breakers and inspect buss


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## chris.b (Jan 28, 2013)

emtnut said:


> Re-read your post ... the customer got new appliances ...
> 
> The old appliances had neutral tied to ground, thereby completing the circuit:thumbup:
> 
> **edit*** One neutral bar is actually ground !!!


We have a winner. Inspector missed the 2/0 on the 200 amp disconnect and the neutral bar.

I think that this panel came this way or someone took the jumper out. The bonding screw was on the left side to bond the box. 

It is amazing how much was wrong in this house and there was never a problem. That we know of that is.

Thanks for playing.


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## emtnut (Mar 1, 2015)

chris.b said:


> We have a winner. Inspector missed the 2/0 on the 200 amp disconnect and the neutral bar.
> 
> I think that this panel came this way or someone took the jumper out. The bonding screw was on the left side to bond the box.
> 
> ...



What do I win :blink:

:laughing:


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## Bootss (Dec 30, 2011)

emtnut said:


> I think we're on to something :thumbsup:


So:
2-hots
1-neutral
1-grounding electrode conductor or equipment grounding conductor

On new appliances maybe got connected wrong?
:vs_cry::vs_cry::vs_cry:


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## chris.b (Jan 28, 2013)

Lep said:


> So:
> 2-hots
> 1-neutral
> 1-grounding electrode conductor or equipment grounding conductor
> ...


Old appliances were connected wrong. New ones are wired right.


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## emtnut (Mar 1, 2015)

Lep said:


> So:
> 2-hots
> 1-neutral
> 1-grounding electrode conductor or equipment grounding conductor
> ...


Nahh ... chit like that never happens :laughing:


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## Bootss (Dec 30, 2011)

chris.b said:


> Old appliances were connected wrong. New ones are wired right.


6 years old house not very long ago.

Would think that both appliances and house wiring system have a 4 wire system . How were old appliance hooked up and how are they hooked up now?

:vs_cry::vs_cry::vs_cry:


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## RePhase277 (Feb 5, 2008)

So the probably #10 ground and white to the stove/oven were carrying all of the neutral current of that half of the panel. Good catch.:thumbsup:


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## chris.b (Jan 28, 2013)

InPhase277 said:


> So the probably #10 ground and white to the stove/oven were carrying all of the neutral current of that half of the panel. Good catch.:thumbsup:


Exactly. Most likely the dryer as well, but didn't check. I was satisfied with my conclusion. Both were landed on the left side of the panel.


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## RePhase277 (Feb 5, 2008)

Lep said:


> 6 years old house not very long ago.
> 
> Would think that both appliances and house wiring system have a 4 wire system . How were old appliance hooked up and how are they hooked up now?
> 
> :vs_cry::vs_cry::vs_cry:


Many of the ground and neutral wires on new appliance whips are crimped electrically together. It is up to the installer to seperate them during a 4-wire install... a Lowes delivery driver doesn't give a crap about 3-wire vs. 4-wire.:laughing:


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## Bootss (Dec 30, 2011)

InPhase277 said:


> Many of the ground and neutral wires on new appliance whips are crimped electrically together. It is up to the installer to seperate them during a 4-wire install... a Lowes delivery driver doesn't give a crap about 3-wire vs. 4-wire.:laughing:


Do they crimp them on the inside of the appliance or on the outside where the wires are at the end of the whip?
:devil::devil:


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## backstay (Feb 3, 2011)

chris.b said:


> I knew someone would say something about the "phases". But that is ok. You caught that, but you missed the 200 amp Disconnect part. The panel rating doesn't matter to the wire size in this situation. It could be a 225 amp and wouldn't matter. Worse if it was 125.
> 
> I gave you all the information. Read it again.


I stand by the wire being too small. The 200 amp is feeding 2/0 AL, it's too small. The MLO rating is the question. And you had a bad neutral.


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## Bootss (Dec 30, 2011)

emtnut said:


> Re-read your post ... the customer got new appliances ...
> 
> The old appliances had neutral tied to ground, thereby completing the circuit:thumbup:
> 
> **edit*** One neutral bar is actually ground !!!


All this can get screwy Louie pretty quick.
:help::help::surrender::surrender:


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## chris.b (Jan 28, 2013)

backstay said:


> I stand by the wire being too small. The 200 amp is feeding 2/0 AL, it's too small. The MLO rating is the question. And you had a bad neutral.


The wire is too small for a 200 amp disconnect. The wire was wrong for the 150 amp because it was protected by the 200 amp disconnect. The wire would be wrong for a 200 amp panel as well because it was protected by the 200 amp disconnect. Or you could just say that the disconnect was wrong. Either way the disconnect didn't match the wire or the wire didn't match the disconnect or the disconnect didn't match the panel or the wire. It was wrong and the inspector didn't catch it.

Neutral conductor from the disconnect was fine and landed on the right side neutral bar. There was no neutral conductor or jumper to the left neutral bar. All grounds landed on ground bar.


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## macmikeman (Jan 23, 2007)

Some other ways the neutrals get connected together is inadvertently at multi gang switch boxes where more than one neutral home run was in the box, but installer (notice I didn't call the guy an electrician wink wink...) tied them all together in one big blue wire nut ........ By the time that electricity got all done running way out to the switches and back it was mighty dizzy and lost a couple of volts when it sat down to rest...


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## chris.b (Jan 28, 2013)

Now the one concern that I do have is what size jumper do I need to have between the 2 neutral bars? #6 cu is the biggest wire that I had on the truck that would fit without adding bigger lugs to both bars. I believe that it will be sufficient, but how do you calculate that? What is the factory jumper equivalent to?


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## papaotis (Jun 8, 2013)

depends on the panel. with a solid metal bar, probly 1000a. some have a #6 solid wire. that should suffice never hadone that wasnt connected from the factory.


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## Bootss (Dec 30, 2011)

chris.b said:


> Now the one concern that I do have is what size jumper do I need to have between the 2 neutral bars? #6 cu is the biggest wire that I had on the truck that would fit without adding bigger lugs to both bars. I believe that it will be sufficient, but how do you calculate that? What is the factory jumper equivalent to?


You need to hit the two neutral buss bars and the ground busbar ,correct? (Tie in the ground to that disconnect also)
:vs_shocked::vs_shocked::vs_closedeyes:


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## A Little Short (Nov 11, 2010)

Lep said:


> You need to hit the two neutral buss bars and the ground busbar ,correct? (Tie in the ground to that disconnect also)
> :vs_shocked::vs_shocked::vs_closedeyes:


No, no, no!

Don't hit the ground bar with the jumper, it's a subpanel!


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## mikesparky (Aug 1, 2015)

can some one help me figure this out as a apprentice? to me if i read 120v phase to ground that would tell me that both the grounding and one of the hot legs are functioning properly. then if i got 90 volts on the other leg to ground,that would tell me there is a issue with that particular leg. now if it did this under load that is different . As long as there isn't a disconnect in place that would require the panel to not be bonded. i can't see how the voltage is going to be affected as every thing is bonded through the panel it self?


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## just the cowboy (Sep 4, 2013)

*Neutral problem*



mikesparky said:


> can some one help me figure this out as a apprentice? to me if i read 120v phase to ground that would tell me that both the grounding and one of the hot legs are functioning properly. then if i got 90 volts on the other leg to ground,that would tell me there is a issue with that particular leg. now if it did this under load that is different . As long as there isn't a disconnect in place that would require the panel to not be bonded. i can't see how the voltage is going to be affected as every thing is bonded through the panel it self?


His 90 v was to the neutral on the left not a phase issue. The ground and neutral are not bonded in that panel but in the disconnect.


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## Anathera (Feb 16, 2016)

Obviously this problem has been solved, we used to have a similar deal show up when one of the fuses outside on our duplexes would blow, all the lights on that leg would keep burning at half power, cfls would go crazy. Took us awhile to figure out how it was getting juice with a blown fuse, turns out it would actually route power from the opposite leg through the water heater. Shut off that breaker and the first leg died.


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## PlugsAndLights (Jan 19, 2016)

Well, this thread just made an interesting read. Thanks.:thumbup: 

BTW, I'm in the camp that refers to the two 120's as phases. 
I was an electronic technologist for 20 years or so before becoming 
an electrician. The convention of only recognizing voltages as phases
if they're 120deg out of phase with each other still mystifies me.
120/240 is 2 phases 180deg out of phase with each other.


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## emtnut (Mar 1, 2015)

PlugsAndLights said:


> Well, this thread just made an interesting read. Thanks.:thumbup:
> 
> BTW, I'm in the camp that refers to the two 120's as phases.
> I was an electronic technologist for 20 years or so before becoming
> ...



It's one phase ... just center tapped


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## PlugsAndLights (Jan 19, 2016)

emtnut said:


> It's one phase ... just center tapped


And when you center tap that phase, you create 2 phases 180deg 
out of phase with each other *. Pretty sure we're saying the same 
thing, we just have different preferences when it comes to the 
conventions used to describe it. Again, my preferences were formed
in my electronics days. 

*wrt (with respect to) neutral/ground. 

On an analogous note: Some guys call them #2 Robertson screw 
drivers while others call them #8's. While I consider them to be 
#2's, I usually call them red robertons and avoid the whole thing.


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## emtnut (Mar 1, 2015)

PlugsAndLights said:


> And when you center tap that phase, you create 2 phases 180deg
> out of phase with each other *. Pretty sure we're saying the same
> thing, we just have different preferences when it comes to the
> conventions used to describe it. Again, my preferences were formed
> ...


We're saying the same thing, and I know what you mean :thumbsup:

fwiw ... It's a #2 or a red handled :laughing:


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## PlugsAndLights (Jan 19, 2016)

chris.b said:


> I went to look at a panel that customer said had 90 volts to all circuits that were on the breakers installed on the left side of the panel but had 122 volts to the breakers on the right. As it turned out he was right, but only if you read it from the breakers on the left to the neutral bar on the left. If you read it from each phase to the neutral bar on the right, it read around 122 on both phases, 90 on the left. 122 to ground. This was a Cutler Hammer BR main lug panel.
> 
> This house is over 6 years old, and has not had any problem until now. New owner has been in this house for a month. The appliances came with the house. But, she decided to buy new appliances and that is when she started having problems.
> 
> ...


So I read this thread beginning to end and it all seemed to make sense.
But thinking about it further, I'm not so sure. With the left neutral bar 
not connected and therefore floating, it should become the central point
of a simple series voltage divider. If phase A to the floating neutral bar
is 90V then phase B to the same neutral bar should be about 150V. 
This would apply whether the voltage was measured from left or 
right side breakers to the left/floating neutral bar. 
Put another way: If phase A to phase B on the left side breakers reads
240V and both phases read 90V to the left side neutral bar, what happened
to the other 60Volts?


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## guest (Feb 21, 2009)

PlugsAndLights said:


> So I read this thread beginning to end and it all seemed to make sense.
> But thinking about it further, I'm not so sure. With the left neutral bar
> not connected and therefore floating,_* it should become the central point
> of a simple series voltage divider. *_If phase A to the floating neutral bar
> ...


What I highlighted is the key point..since the LOADS on the floating neutral buss were most likely not the same as the loads on the "good" neutral buss, it would make for a very uneven split of the L-N voltages. 

(Basically, what happened in the OP's case was you had TWO separate "services" if you will existing in the same panel. One, the proper one, had the two lines and a proper neutral, the second had the two lines and a floating "center tap" acting as a floating neutral. )

Bizarre for sure and a good find by the OP.


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## Bootss (Dec 30, 2011)

So the right side neutral and the grounding conductor were connected together at the disconnect, and left side of the panel neutral was not hooked to anything in the system.

Then apparently the old appliances were hooked in a way to where the neutral and grounding conductor all went back to the disconnect and they worked correctly. Then they installed new appliances and hook them up into a 4 wire system and that's when you got the problem.

So the solution was to tie the left side neutral together with the right side neutral and then that went to the disconnect and tied together with the ground.
:vs_cry::vs_smirk::vs_cry::vs_smirk:


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## emtnut (Mar 1, 2015)

PlugsAndLights said:


> On an analogous note: Some guys call them #2 Robertson screw
> drivers while others call them #8's. While I consider them to be
> #2's, I usually call them red robertons and avoid the whole thing.


So ... Are they 3-way switches, or 2-way switches :laughing::laughing::laughing:

Or if the switch combination is binary, they should really should be called 4-way switches :jester:


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## macmikeman (Jan 23, 2007)

pox on Robertson


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## retiredsparktech (Mar 8, 2011)

InPhase277 said:


> Many of the ground and neutral wires on new appliance whips are crimped electrically together. It is up to the installer to seperate them during a 4-wire install... a Lowes delivery driver doesn't give a crap about 3-wire vs. 4-wire.:laughing:


How can those whips pass U/L inspection? I've never seen one. The separate ground and neutral has been around for how long?
When Sears delivered my dryer and range in 2003, they wanted to connect it, with the neutral and ground connected together. They heard about it big time.


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## RePhase277 (Feb 5, 2008)

retiredsparktech said:


> How can those whips pass U/L inspection? I've never seen one. The separate ground and neutral has been around for how long?
> When Sears delivered my dryer and range in 2003, they wanted to connect it, with the neutral and ground connected together. They heard about it big time.


The way I think about it is it would be better for them to accidentally ground it to the neutral than it would be to leave it ungrounded completely, which is likely what would happen if the two wires were separated.


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## shloshaff (Jun 2, 2013)

chris.b said:


> DING DING DING!!!! It had NOTHING tying them together!!!
> 
> Now how did work for so long?


left side bar is ground bar not nuetral


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## A Little Short (Nov 11, 2010)

shloshaff said:


> left side bar is ground bar not nuetral


Not necessarily nor always. OP mentioned having a ground bar. If the left side bar is floating to ground (isolated from the cabinet) and also from the right side bar, then it was just a mistake that it wasn't bonded to the right side. If it isn't mounted directly to the cabinet, with no plastic insulator, then it was never meant to be a ground bar.


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## shloshaff (Jun 2, 2013)

A Little Short said:


> Not necessarily nor always. OP mentioned having a ground bar. If the left side bar is floating to ground (isolated from the cabinet) and also from the right side bar, then it was just a mistake that it wasn't bonded to the right side. If it isn't mounted directly to the cabinet, with no plastic insulator, then it was never meant to be a ground bar.


I know this panel. have worked on many such panels. Also oloder equipment would accept a ground as a nuetral being that even the appliances with computer chips weren't internally checking power. Most newer appliances have internal controls that won't allow them to run unless they are getting a proper read of 120. So when testing to left bar only getting 90 would work on older appliances but not newer ones.


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## Anathera (Feb 16, 2016)

Siemens panels are the same set up often, where the left bar can be either a ground or a neutral depending on what you bond to


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## mikewillnot (Apr 2, 2013)

> 200 amp disconnect. 2/0 Al SER feeds the main lug panel in the house


Maybe I'm missing something, but I thought 4/0 AL was required for 200 amps.


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## Missouri Bound (Aug 30, 2009)

PlugsAndLights said:


> Well, this thread just made an interesting read. Thanks.:thumbup:
> 
> BTW, I'm in the camp that refers to the two 120's as phases.


Me too. But it was hard to explain to homeowners.
I started saying "legs" referring to the incoming hot lines instead of phases.
Since 120/240 residential is single phase it made is simpler to explain.:whistling2:
Most homeowners could care less or understand about 3 phase.


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