48windsor
Well-known member
Im going to make a single pole light switch into a hall or three pole switch, The new switch will be next to an existing light switch on a different circuit, in same box is it legal .or to code . I live in Wa.
more than one circuit in a gang box
- Thread starter 48windsor
- Start date
alfredeneuman
Well-known member
The voltage limit rule for switches next to each other on different circuits:
NEC 404.8
(B) Voltage Between Adjacent Devices. A snap switch shall not be grouped or ganged in enclosures with other snap switches, receptacles, or similar devices, unless they are arranged so that the voltage between adjacent devices does not exceed 300 volts or unless they are installed in enclosures equipped with identified, securely installed barriers between adjacent devices.
You're good to go
NEC 404.8
(B) Voltage Between Adjacent Devices. A snap switch shall not be grouped or ganged in enclosures with other snap switches, receptacles, or similar devices, unless they are arranged so that the voltage between adjacent devices does not exceed 300 volts or unless they are installed in enclosures equipped with identified, securely installed barriers between adjacent devices.
You're good to go
wyliesdiesels
Well-known member
In other words, u cant put a 120v and a 480v switch in the same box.
forAK
Well-known member
Where would you find a barrier for a 3 gang plastic box? I've got 3 home run light switches in a single box. Seeing this means I've got to fix it.
dave*99
Well-known member
Read his post again. Do you have greater than 300 volts between adjacent light switches in your installation?
forAK
Well-known member
3 home runs - 1 each 120v going to 1 each 15 amp breaker. Yes, 360v in 1 3 gang plastic box. Therefore, where would I find barriers to securely install?
mike93lx
ALLIANCE MEMBER
Difference not total. Read the post again
forAK
Well-known member
LOL! Got it!
Thank you all , for your help I will rest at ease.
Really , trying to keep it convenient I have a light switch r tou tof man door,walk a few steps and garage hooks and there is another circuit /light switch for another bank of lights. So I will be able to turn on lights to hook in garage and not have to get my icecream in the dark .
I guess it doesnt matter which circuit I tap off of than either
Really , trying to keep it convenient I have a light switch r tou tof man door,walk a few steps and garage hooks and there is another circuit /light switch for another bank of lights. So I will be able to turn on lights to hook in garage and not have to get my icecream in the dark .
I guess it doesnt matter which circuit I tap off of than either
wyliesdiesels
Well-known member
Metering from hot to hot u will NOT have more than 120v difference between 2 ungrounded conductors.
As i pointed out in comment #3, u would have to have a 480v service and a seperately derived 120v service in order to have 300v+ difference between the 2 ungrounded conductors.
Marctrees
Well-known member
"Metering from hot to hot u will NOT have more than 120v difference between 2 ungrounded conductors." ("Hots")
I think Wylie meant to say 240 max, not 120 max.
Not being a jerk, Do not want to step on toes, but I am pretty sure it was a honest mistype.
Wylie - Please correct me if I'm wrong.
I'm pretty sure, metering from the one ungrounded to the other ungrounded, will give you either "0", or 240, depending on which Hot leg in the panel they are fed from.
Re the OP question - it's not rare to have ckts from separate breakers in j boxes, but usually see that in non residential work.
48Windsor - Re: location of your new 3way sw - How do you mean - specifically- it will be "next to"?
How will you be adding a new switch "next" to an existing one.
It may matter, so tell please.
Marc
I think Wylie meant to say 240 max, not 120 max.
Not being a jerk, Do not want to step on toes, but I am pretty sure it was a honest mistype.
Wylie - Please correct me if I'm wrong.
I'm pretty sure, metering from the one ungrounded to the other ungrounded, will give you either "0", or 240, depending on which Hot leg in the panel they are fed from.
Re the OP question - it's not rare to have ckts from separate breakers in j boxes, but usually see that in non residential work.
48Windsor - Re: location of your new 3way sw - How do you mean - specifically- it will be "next to"?
How will you be adding a new switch "next" to an existing one.
It may matter, so tell please.
Marc
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wyliesdiesels
Well-known member
notice i said difference?
Measuring hot to ground gives 120v so measuring hot to hot(240v) gives a 120v difference.
this subject is about the code above and the voltage difference between 2 hot conductors.
Marctrees
Well-known member
We may be talking about two different things.
Probably more of a language misunderstanding on my part.
All I meant was- if there are two hots from two different breakers in a typical residential situation, and meter is put across those two hots, you will read either 0, OR 240 - 50/50 chance, depending on which leg of the service they are fed from.
No?
Otherwise, it's ok.
I'll step away. Marc
Probably more of a language misunderstanding on my part.
All I meant was- if there are two hots from two different breakers in a typical residential situation, and meter is put across those two hots, you will read either 0, OR 240 - 50/50 chance, depending on which leg of the service they are fed from.
No?
Otherwise, it's ok.
I'll step away. Marc
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Marctrees
Well-known member
And I also don't understand the thread going to that code article, cause at most hes got 240, unless he lives in some NY warehouse loft .
And noone brought up the commoness of more than one ckt in a given box. Marc
And noone brought up the commoness of more than one ckt in a given box. Marc
The NEC quote normally applies to 277 volt lighting circuits, when circuits on different phases are adjacent to each other, 480 volts is present which means more then 300 volts and the barrier requirement kicks in, since those voltages are not normally found in a residence ( I did come across residential 277V lighting once though) the barrier is not required since the maximum voltage present will be 240 volts. There is nothing to worry about, go for it.
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alfredeneuman
Well-known member
Marctrees, I hope I can explain it clearly : Picture a single light switch outside of a directaccess door to garage. Walk a few steps hook left and another switch on wall for a different set of lights. so what I want to do is go from hook in garage back to direct access switch with a threeway switch ,putting new switch in same box as exixting switch outside of man door. In so doing I can turn on lights to hook from direct access or from the hook which at times will be nice.
I hope I was clear enough and makes sense
I hope I was clear enough and makes sense