Basic Grounding question

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Old 01-31-16, 08:32 PM
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Basic Grounding question

Can all the grounding wires be connected to the grounding screw on the device ?
(either a switch or receptacle or even porcelain light fixture)

Rather then create a pigtail which in effect requires four wires(one wire to device, one to metal box, one incoming from cable feeding box and one outgoing from cable leaving box) is it acceptable to connect all the ground wires directly to the green screw on the device allowing there to be one less grounding wire?
 
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Old 01-31-16, 08:44 PM
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No. One wire per screw. Box fill counts the total grounds as "1" not each so nothing would be gained.
 
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Old 01-31-16, 08:50 PM
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The wires would be very hard to secure properly under one screw head. Follow the advice above.
 
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Old 02-01-16, 06:09 PM
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The only issue I find is it requires adding an extra wire to each box which can make things fairly crowded in the box. It seems neater and more roomier doing it the other way. Putting code aside for the moment - electrically what is the a? Are you not accomplishing the exact same thing?


Must each individual metal box along the circuit be grounded? It seems like not infrequently when I open up a box in my "older" house - whether to change a switch or receptacle very often there is no separate ground wire going to a screw on the box. Often the grounds from the incoming and outgoing cables are wrapped around the grounding screw on the device or if there is no outgoing cable the ground is just attached to the grounding screw on the device. Does this pose a danger? If it is a receptacle in the box and I use a tester it will read that it is grounded despite there being no ground to the box.
 
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Old 02-01-16, 08:47 PM
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Grounding requirements have changed over the years.

Trying to stack 4 wires under a screw head will not give a reliable connection.
 
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Old 02-02-16, 08:01 AM
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Code requires an unbroken mechanical connection (wirenut, screw terminal, crimp) on ground wires, and ground integrity cannot depend on the device. In other words if you remove the receptacle, the rest of the circuit must still be grounded. In fact grounds must be fully made-up and continuous prior to rough inspection when power isn't even turned on yet. If the grounds were spliced on the device screw, this requirement would be violated.

If you really want to save box space you can use a barrel crimp and leave one of the ground wires long to wrap the device screw. That takes almost no space, but is harder to rework in the future if necessary.
 
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