Two circuits feeding one load

[480sparky]

Rick, look at post # 11, this is simply a one line diagram and the grounded conductor is not shown.

Roger

You mean this?

 

[roger]

Is this a more accurate drawing?

Now you have burned up the 120 volt load by supplying it with 240 volts.

Go back to the original illustration and think about it.

Roger

 

[roger]

You mean this?

Yes.

Roger

 

[480sparky]

Now you have burned up the 120 volt load by supplying it with 240 volts.

Go back to the original illustration and think about it.

Roger

Where is it stated the load is 120v?

Yes.

Roger

You've overloaded the neutral, then.

 

[roger]

There will be zero volts across the loads.

Draw it out with arrows for current flow, you will see a complete 40 amp circuit.

BTW, after the load we will definitely see zero volts.

Roger

 

[76nemo]

It won't work that way anyway.... they're on the same phase, so there's no voltage.

Wha, for a minute, I thought my mind was goings nuts, (frig)?????

 

[480sparky]

Draw it out with arrows for current flow, you will see a complete 40 amp circuit.

BTW, after the load we will definitely see zero volts.

Roger

"What we have here is a failure to communicate."​

You quoted me before I could edit my response.

 

[roger]

Where is it stated the load is 120v?

Look at the illustration. :roll:




You've overloaded the neutral, then.

Wrong.

Once again, your taking a simple one line diagram and not thinking it through, both sides of the circuit would be identical, i.e., they would both have a grounded conductor. (not a neutral)

Roger

 

[480sparky]

Wrong.

Once again, your taking a simple one line diagram and not thinking it through, both sides of the circuit would be identical, i.e., they would both have a grounded conductor. (not a neutral)

Roger

And it would carry the sum of the amps coming from both breakers. This is not a MWBC.

 

[roger]

And it would carry the sum of the amps coming from both breakers.

Yes it would.

Think of taking a 40 amp single pole breaker and running two equal #12 conductors to a single 40 amp heating element, if you were to put an ammeter on the conductors one at a time they would be carrying 1/2 the load current which would be 20 amps.

Feeding two individual conductors with 20 amp breakers on the same leg or phase would achieve the same results.

Of course this is a violation of 240.8 in the real world.

Roger

 

[RUWired]

Yes it would.

Feeding two individual conductors with 20 amp breakers on the same leg or phase would achieve the same results.


Roger

of course this can't be a real situation because of field conditions and use. Having a disclaimer in the instructions to install on the same phase would'nt work unless the unit was rated for a maximum 240 volt

 

[roger]

of course this can't be a real situation because of field conditions and use. Having a disclaimer in the instructions to install on the same phase would'nt work unless the unit was rated for a maximum 240 volt

Why? In this exercise the unit is is 120 volt and would fry on a higher voltage.

Roger

 

[480sparky]

Yes it would.

Think of taking a 40 amp single pole breaker and running two equal #12 conductors to a single 40 amp heating element, if you were to put an ammeter on the conductors one at a time they would be carrying 1/2 the load current which would be 20 amps.

Feeding two individual conductors with 20 amp breakers on the same leg or phase would achieve the same results.

Of course this is a violation of 240.8 in the real world.

Roger

But in order for current to flow, it would need the grounded conductor, so in effect you would have this:

 

[roger]

But in order for current to flow, it would need the grounded conductor, so in effect you would have this:

Now your catching on!

I think we are getting somewhere now.

The problem is you're still trying to look at the load as being two.

Roger

 

[480sparky]

Yes it would.

Think of taking a 40 amp single pole breaker and running two equal #12 conductors to a single 40 amp heating element, if you were to put an ammeter on the conductors one at a time they would be carrying 1/2 the load current which would be 20 amps.

Feeding two individual conductors with 20 amp breakers on the same leg or phase would achieve the same results.

Of course this is a violation of 240.8 in the real world.

Roger

By what you're saying here, this is what you have:

No current can flow because there is no circuit.

 

[RUWired]

Why? In this exercise the unit is is 120 volt and would fry on a higher voltage.

Roger

That is my point about not being field friendly. Guy comes in and finds only two spaces open (pole position 1 and 3).Turns it on and smoke.Or am i missing the whole thing. He should be using a 40 amp single pole but only has two single 20's on the truck.

 

[roger]

By what you're saying here, this is what you have:

No current can flow because there is no circuit.

Why did you get rid of the grounded conductor? You have just lost all that you had learned.

Roger

 

[roger]

That is my point about not being field friendly. Guy comes in and finds only two spaces open (pole position 1 and 3).Turns it on and smoke.Or am i missing the whole thing. He should be using a 40 amp single pole but only has two single 20's on the truck.

Rick, if the circuit is fed from the same leg or phase it will never be in jeopardy of a higher voltage.

Roger

 

[480sparky]

Why did you get rid of the grounded conductor? You have just lost all that you had learned.

Roger

So what is the difference between these two?

 

[RUWired]

Rick, if the circuit is fed from the same leg or phase it will never be in jeopardy of a higher voltage.

Roger

I know roger,i'm laughing at the whole sinerio.