Another wiring Question

[Halfathumb]

On my Square D panel (installed 1998) there's many 120V wires that have the neutral & ground connected to the same bus (?). Is that an old practice that is now taboo? I use the word "bus" because that's what I heard on one of the videos, meaning ground bar.

[Mike 55]

On my Square D panel (installed 1998) there's many 120V wires that have the neutral & ground connected to the same bus (?). Is that an old practice that is now taboo? I use the word "bus" because that's what I heard on one of the videos, meaning ground bar.

The Neutral and Ground are generally connected together at your service panel, not at your devices.


At the device, neutral is the path for return current. All the current that comes "from" the hot leg "returns" through the neutral wire. I'm using quote marks because current actually alternates directions in an AC system. Hence the name AC!

Anyway, the ground wire should only carry current in the case of a fault condition. In the USA, residential ground wires are often just bare, uncovered copper. When plugging in a grounded appliance or other device, the ground wire gets attached to the chassis.

Say, for example, that the insulation on your hot wire gets damaged and the conductor comes into contact with the metal body of your washing machine. The current shorts through the chassis and then through the ground wire. This high current causes your circuit breaker (or fuse) to trip. If you didn't have the ground wire then the mains voltage would electrify the entire chassis. Then the next person touching it becomes the return path.  
 

So to answer your question this is the normal practice. The new breakers are arc protected. These came out around 2000 and are required for bedrooms etc. 

[Halfathumb]

The Neutral and Ground are generally connected together at your service panel, not at your devices.


At the device, neutral is the path for return current. All the current that comes "from" the hot leg "returns" through the neutral wire. I'm using quote marks because current actually alternates directions in an AC system. Hence the name AC!

Anyway, the ground wire should only carry current in the case of a fault condition. In the USA, residential ground wires are often just bare, uncovered copper. When plugging in a grounded appliance or other device, the ground wire gets attached to the chassis.

Say, for example, that the insulation on your hot wire gets damaged and the conductor comes into contact with the metal body of your washing machine. The current shorts through the chassis and then through the ground wire. This high current causes your circuit breaker (or fuse) to trip. If you didn't have the ground wire then the mains voltage would electrify the entire chassis. Then the next person touching it becomes the return path.  
 

Thanks Mike. I was only speaking of the service panel connections. I just never paid that much attention to that before. Thanks for the electricity 101 information.

Jim

[Roly]

Thanks Mike. I was only speaking of the service panel connections. I just never paid that much attention to that before. Thanks for the electricity 101 information.

Jim

 Only if that panel is the first point the neutral is grounded can they be mixed.   If it is a sub panel they should be kept separate.  Roly

[EdL]

 Only if that panel is the first point the neutral is grounded can they be mixed.   If it is a sub panel they should be kept separate.  Roly

I always seperate them in any panel, IMO, looks cleaner and more professional.

Ed

[GeeDub]

I always seperate them in any panel, IMO, looks cleaner and more professional.

Ed

Oh no!  You've awoken the code cops

[Halfathumb]

Oh no!  You've awoken the code cops

Can I still ignore them? 

[Sam Hightower]

NEC requires isolated neutral bus since 1997. Had to rework my entire panel because the rules changed in the middle of my house build.

[crokett™]

I always seperate them in any panel, IMO, looks cleaner and more professional.

Ed

I hope you did not wire the main panel in your house.  The main panel must have a tie bar between the ground and neutral buses.  Most panels sold as main panels don't have separate buses anyway.  Grounds and neutrals all go on the same bus.  All the other sub panels that feed off that main you remove the tie bar if it is installed.  It's not a a question of professional, it's a question of safety and the way it is supposed to be done.  Now you can do a professional job and wire things neatly so it's not all higgledy-piggledy in the panel.

[Halfathumb]

 higgledy-piggledy in the panel.

Is that technical terminology? Just like to know for future considerations.