Electrician Question - Connecting detached garage

[ksa8907]

You're not supposed to, I know you're not supposed to, and i know there's a reason you're not supposed to. That's about the extent of my electrical knowledge.

[redpoint5]

Hehe, looks like I might be able to tell you first hand why you're not supposed to very soon. 120v is pretty tame.

[freebeard]

What is the purpose of removing the bonding in the sub, but not in the main panel?

Visuals probably helps explain these questions.

I interpreted that as for test purposes to identify the two lines.

2x on circuit diagrams help. Earth is ground but there are telluric currents flowing there. I don't know the scale but dirt is probably an insulator. Massive grounds to bedrock let you do some weird stuff. Like Tesla's Wydencliffe tower.



In the video those plasma jets are making a hissing sound.

[oil pan 4]

With a sub panel you have to run a neutral and a ground if you are running 120/240v power on the sub.
If it's a 240v only you don't have to run a neutral.

The reason why the neutral ground bond is broken in the sub panel is so the ground doesn't carry current.
If the neutral and ground are bonded at the sub then the ground acts like a neutral. Then you won't know there is a neutral or broken ground fault until you lose both.

[Piotrsko]

Originally Posted by redpoint5

Hehe, looks like I might be able to tell you first hand why you're not supposed to very soon. 120v is pretty tame.

May not happen on connection, but could on first rainfall or really dry day or anything in between. I believe it is because dirt is a semiconductor with abnormal properties. I also know that neutral is not necessarily at ground potential.

120 might be tame enough to kill. Just like chuck yeager and the super cub "the worlds safest airplane, with just enough power to barely kill you"

I defer to oilpan's experience, as I am a signals tech that also kinda does power.

[redpoint5]

Well, neutral and ground would be at the same potential if they are both bonded in both panels. Heck, they should be at just about the same potential if they are only bonded in 1, as a grounded neutral from one panel wired to the other would also drive it to equal.

I'm still unclear if the "sub" panel at the old house should be unbonded once I wire things up.

[oil pan 4]

Sub panels are never to have the neutral and ground bonded.
The neutral does have some potential difference to ground depending on the load but it should never exceed 10 volts during normal conditions, ideally it's only around 3 volts.
Balanced load will also help reduce the voltage difference to ground on the neutral.