Electrical Question?

These little panels are cheap adn very easy to install. That's the safe and right way to go at it.

I've got 1 sub in the garage with 4 wire 240 to it, but I better look at the neutral and ground - I be they're tied on whichever side the breakers want the hot wire to be.

John T

I don't quite understand the solution you propose unless you're assuming that the 220 conductor is already the 4 wire configuration. Otherwise, wouldn't you have to use the ground as the neutral in the new sub panel, and incur all the crossover problems that most of the previous posts warn against?

All the best, Stan

Gerald J. Electrical Engineer.

First of all ONLY the 110/120 volt branch circuit requires and makes use of the white Neutral (a grounded conductor), the 220/240 volt circuit DOES NOT REQUIRE OR USE ANY NEUTRAL, its line to line. A branch circuit to feed a 220/240 volt motor would carry the bare/green safety equipment ground, but it does not use or require any white Neutral since its ONLY 220/240 votls thats used.

Next: Its ONLY at the service entrance main panel where the Neutral Buss and the Equipment Ground Busses are bonded together NEVER AGAIN DOWNSTREAM AT ANY SUB PANELS i.e. if the main service entrance panel was used to feed a smaller sub panel at a remote location in the house or atatched garage, you would have to run 4 wires to it, 2 Hots, 1 White Neutral (grounded conductor), 1 bare/Green Safety Equipment Ground (grounding conductor) and at that sub panel the Neutral Buss and the Equipment Ground Busses would be seperate and isolated NOT re bonded.

That being said, if you want 110/120 volt at some location you need to use one of the hots and a white Neutral (grounded conductor) then the bare/green safety equipment ground if its a 3 wire grounding type receptacle. If its only a 2 wire receptacle, that would be a hot and Neutral.

NOTE AND CAUTION: DO NOT use the bare/green safety equipment ground (grounding conductor) to carry return current for use on 110/120 volt. Its a violation of the NEC and a safety issue. The bare/green equipment ground (grounding conductor) is only to provide a low impedance current path back to the panel to trip the breaker and save lives. The Neutral (grounded conductor) is intended to carry return current back to the panel i.e use a hot and neutral for 110/120 volts.

NOWWWWW WWW sure I know it will work and its been done and how the older ranges and dryers will work and feed 110/120 volts while using the bare/green safety equipment ground to carry return current Yeah Yeah Yeah, Blah Blah Blah I knowwwww wwww those two (Neutral and Ground) busses are indeed bonded together at the service entrance panel.

ALLLLL LL IM SAYING IS TO USE THE BARE/GREEN SAFETY EQUIPMENT GROUND (a grounding conductor) TO CARRY RETURN NEUTRAL CURRENT IS A VIOLATION OF THE NEC AND CAN CREATE A SAFETY HAZARD.

Its your house do as you wish but as a retired electrical power distribution design engineer (BSEE Purdue 1969) I only feel right to give you the proper, safe and NEC approved advise.

SOOOOO OOOOO OO if you need to tap off 110/120 thennnnn nnn you need a branch circuit that has a white Neutral (Cant Use the bare/green safety equipment ground per the NEC). If you require BOTH 110/120 and 220/240 THENNNNN the branch circuit requires FOUR WIRES, 2 Hots, 1 Neutral (for the 110/120), 1 Safety Equipment Ground

Best wishes, God Bless and yall have a safe n happy new year

John T

You see the electricity is seeking a current path back to the service transformer (thats where the voltage difference is) and earth isnt a good path. However, if you run that 4th equipment grounding conductor from the main to sub panel (as we told you), it IS A GOOD LOW IMPEDANCE CURRENT RETURN PATH back to the transformer (to trip a circuit breaker to save your life) via the Neutral and Ground busses being tied at the main panel which is served by the transformer.

The reason the Neutral, at BOTH the pole or pad mount transformer, PLUS at the service entrance is tied to a grounding electrode (driven rods or water or gas pipes) to Mother Earth is to bring everything back down to a common zero reference. That driven ground rod you wanted to use simply DOES NOT suffice as a good return current path back to the panel to trip a circuit breaker to clear a dangerous fault.

RUN 4 WIRES TO THE SUB PANEL FOR 120/240 VOLT SINGLE PHASE 3 WIRE SERIVICE 2 Hots,,,,, ,1 Neutral,,,,, 1 Equipment Grounding Conductor.

RUN 3 WIRES TO A 120 VOLT LOAD 1 Hot, 1 Neutral, 1 Equipment Grounding Conductor.

Hope this helps

John T retired electrical engineer

Doesn't matter if you use only one at a time, that is a non-issue.

Tying the neutral & ground wire together, (or interchanging them as you hope to do) with the modern devices that use the ground plug or GFI, etc. will now have every metal surface of your tools energised if some little thing goes wrong.

Just how it is in this century. Things have changed over the past 40 years. Our tools are safer, but wiring things up 'just so they work' now makes the whole system more dangerous.

Only responsible thing to tell you is to run a new 4-wire (hot, hot, neutral, ground) wire & do it right.

--->Paul

At 480, the arc isn't self clearing and still doesn't draw enough current to trip a breaker or blow a fuse. I've heard of a wall sized 480 volt panel burning the whole thing as the arc traveled towards the power source.

I had a client that closed a 480 volt switch after checking the fuses. It started to buzz and he raised his hand to shut it off. It blew the door off before he got there and enveloped him in a cloud of copper vapor. Lots of burns, but his hand shielded his face. That one did blow the upstream fuses but they weren't current limit, but where super lag renewables and I was able to account for their delay by the amount of copper vaporized.

I've run into electricians working in a plant with both 240 and 480 and if the boss asked them to work on 480, they waved a scared arm at him and told him where he could go (he could go work on the 480 himself) and didn't work on the 480.

Gerald