Umbra, my friend who does most of my electrical work calls the neutral the ground. That confused me until he showed me the breaker box and that the neutral and the ground are tied together. Then it made sense.
There are some serious misconceptions posted here, in how electrical current flows or works. House fires are one of the major killers in homes today, in this hobby understand electric fundamentals,,,or hire a trusted professional..or die.
1)The neutral and common, serve 2 separate purposes. They are not the same, and are not designed as redundancy in function....
more on this subject at the bottom.
2)There is nothing wrong with breaking/switching a common line, though a breaker isn't the correct/safe way to do it. A knife switch box would serve the purpose much safer, it provides a guaranteed method of breaking both lines(hot-common)at the same time...both are "on" or both are "off". A simple knife switch is commonly used in sole purpose Dryer, Range, Air Conditioner circuits. It must be said that switching the common, has basically no merit or value safety wise.
3)Remember most circuits are designed to operate at 80% of given breaker size, yet wiring size is dictated by 100% of breaker face value. The 20% difference is overshoot for voltage surge from motor/compressor start up, these ratings are dictated by 70 deg F panel temp....if your room space is hot, the breaker overload rating goes DOWN....so a 20amp breaker(single or double pole) is designed for a constant load of 16amp...a 15amp breaker(single or double pole) is designed for constant load of 12amp. Wire size is dictated by max amperage(breaker face value)and length of wire.
4)Residential and commercial voltages can differ, as can certain power companies supply current. This is
partially why you see motor/light/device voltage ratings listed as 208-230v, but your true device capicity will be dictated by YOUR particular supplied current....meaning:Manufacturers ** the public with their fan CFM/light/motor speed output ratings, based on the highest usable device voltage...where in reality your performance value, would be dictated by your individual available current.
5)Myth:A 220v device uses 1/2 the power consumption of a 110v device. It is NOT cheaper or more efficient to run a 220v light/motor, instead of 110v device...it only saves on wire size, that's it.
The Common, ground, and neutral wires are NOT the same:
As simple as possible, what's the REAL difference ?..Most US power companies are using a Y or Delta transformer, meaning 3 hot legs with 1 common. This allows a multitude of available current loads for most customers, for most growers common & ground are used...so let's stick to them.
*Common:Comes off of the transformer, is the return current for the hot leg, has current(feedback)100% time, is used to balance line voltage for consistent feed rate from transformer.
*Ground:Used as a safety, when massive over balance or short circuit cycles to ground(Mother Earth)and faults the breaker. No current flows though the ground as normal operation...it's not considered a part of the apparatus or device.
*Common & ground tied together ???
Why ?, what does this do ?, when should you?, when shouldn't you? This is a little confusing, but VERY important. Most have been mislead as to the function, and safety of this practice.
So now we KNOW that the common & ground are 2 different wires, serving 2 different functions...so why are they tied together ?
A)Where the service lines come into your house/building, to your MAIN panel...the common & ground wires CAN be "bonded" together at the same lug bar. The common comes straight off the pole/transformer, the ground generally goes to 2 x 8' rods drove into the ground outside. The return voltage from the common can return to the pole, the ground if short circuited will take the path of least resistance straight to the rods...like a bolt of lightning does through a tree. So mixing/tying the common & ground at the MAIN panel, presents no problem.
B)For ANY sub-panel the common and ground wires MUST be separated, that's why separate buss bars are provided in service panels today. Because you (generally)don't have ground rods at sub-panel locations, the ground & common must return to the main service panel to provide said function. If you tie the common & ground wires together, a short circuit through the ground could/will use the common as the return path...thus not kicking the breaker. This essentially eliminates your ground safety, and makes for a serious electrical hazard.
Remember the common carries current, the ground only should in a safety/faulty event.
Disclaimer: My intention is solely to clarify any myths surrounding electrical safety, not to debate/argue/insult any other members. I've attempted in the past to educate members on electrical problems, only to end up in a fruitless peeing battle confusing members more. We all have to take responsibility for advice given here, bad nute advice = bad grow...bad electrical advice = burnt house & possible death. In the end we want all growers to safely enjoy and operate their rooms, but not at the expense of family and loved ones well being.