[A Little Short]

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!

 

[mikesparky]

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?

 

[just the cowboy]

Neutral problem

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.

 

[Anathera]

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.

 

[PlugsAndLights]

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.

 

[emtnut]

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.

It's one phase ... just center tapped

 

[PlugsAndLights]

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.

 

[emtnut]

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.

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

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

 

[PlugsAndLights]

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?

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?

 

[guest]

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?

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.

 

[Bootss]

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:

 

[emtnut]

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:

 

[macmikeman]

pox on Robertson

 

[retiredsparktech]

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.

 

[RePhase277]

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.

 

[shloshaff]

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

Now how did work for so long?

left side bar is ground bar not nuetral

 

[A Little Short]

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.

 

[shloshaff]

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.

 

[Anathera]

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

 

[mikewillnot]

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.