All the sudden "110v reverse negative polarity"

[ragtoplvr]

The other problem you have is Knob and tube homes I have seen never have ground wires.

Rewiring is is quite expensive, copper is high now, and the labor is not cheap.

first step is to get the tester, and then you can determine how to fix the incorrectly polarized outlets.

Getting a proper ground on the house is much more difficult.

Rod

[ttpete]

There are lots of homes that don't have grounded outlets. Anything built in the 1950s or before won't have them.

What I think is happening here is that the cable coax shielding is always grounded at the entry point to the house. If an outlet is wired backward, you could see voltage between the supposedly neutral side of the outlet and that external ground connection, and that could have fried the cable box.

Use one of the plug in testers, and if that indicates a reversed connection, check the outlet first. If that's wired OK, you'll have to go back to the breaker panel and check connections there at the breaker for that circuit. The breaker should have the black wire, and the white should go to the neutral bus.

Seeing you have some knob and tube work, the neutral and hot could have been unknowingly transposed in some other place. If that's the case, the simplest fix would be to flip the wires in the outlets.

[kiwi_outdoors]

Street transformer is center tapped
center = zero volts = white wire inside your house
either and of the coil is about 115V relative to center - these go to 2 lugs on your breaker panel (black and black or black and red wires)

so thats the three wires coming into the house

the ground wiring inside the house is a "backup" path for current in case the appliance has a problem

ordinarily grounding is for local safety, so we use an earth rod and ground metal pipes and so forth

your sparking sounds interesting, and warrants a professional to check it out

[jdrocks]

Originally Posted by Ricardo Kuhn

... house even if the panel is newer.

no professional electrician ever made up that subpanel, and i'm betting no building inspector ever put his eyes on it.

time to call a licensed electrician, have him check the whole works.

[Ricardo Kuhn]

Originally Posted by jdrocks

no professional electrician ever made up that subpanel, and i'm betting no building inspector ever put his eyes on it.

time to call a licensed electrician, have him check the whole works.

The electrical master just left, one wire was lose on the receptacle, but except for that everything was fine, well at least he did not find any other funky issues.

Ps: pretty sure I will have my 220V welder wire up at last, the guy is great..

[D.T.]

What did he say about the reverse negative polarity?

[Ricardo Kuhn]

Originally Posted by D.T.

What did he say about the reverse negative polarity?

From what I understand, that in a house this old we did not even have "Ground" so was nothing to worry about, still he did change the wires on the outlets to "code"

[MJS]

I'll bet that loose wire was the neutral or grounded (not ground) conductor. That left the electricity looking for another path back to the transformer. The shield on the cable was it.

Yes it was dangerous. Glad you found a good sparky to fix it.

[Ricardo Kuhn]

Originally Posted by MJS

I'll bet that loose wire was the neutral or grounded (not ground) conductor. That left the electricity looking for another path back to the transformer. The shield on the cable was it.

Yes it was dangerous. Glad you found a good sparky to fix it.

Well hopefully is fix by now, the cable come tomorrow will see what they think..

[PukaWai]

Originally Posted by Ricardo Kuhn

From what I understand, that in a house this old we did not even have "Ground" so was nothing to worry about, still he did change the wires on the outlets to "code"

Did he check out the whole house? Many houses that old still have cloth insulated wires on ceramic standoffs that are downright scary after 90 years or so...

[_cy_]

Originally Posted by PukaWai

Did he check out the whole house? Many houses that old still have cloth insulated wires on ceramic standoffs that are downright scary after 90 years or so...

[Warin]

Originally Posted by MJS

I'll bet that loose wire was the neutral or grounded (not ground) conductor. That left the electricity looking for another path back to the transformer. The shield on the cable was it.

Yep think that is it.

In principle it should not matter what 'polarity' there is in the socket/plug ... neither side should be connected to anything you could touch. In principle. Some people wire 'earths' to the 'center' or 'neutral' depending what place your in. That is not safe unless wired correctly - I'd not trust it unless I checked it myself.

Best practice is to have a separate 'earth' connection that goes to anything you can touch. And goes to 'earth' - metal pipes into the soil or bars driven into the soil.

Good Luck with the house wiring. I've seen lead covered ceramic insulated wiring in use ... removed on sight! Probably 1920 vintage? The house also had lead plumbing pipes for water ... .. it was ok, they were for the cistern (from the overhead flushing tank) not the drinking water.

-------------- Don't trust that cable guy who said "reverse negative polarity" !

[ttpete]

There's a BIG difference between "neutral" and "ground". Neutral is the center tap on the 240 volt secondary winding of the pole top transformer. Ground is either the cold water pipe of the building or a ground rod driven into the soil. Never confuse the two.

[rapidoxidationman]

That cold water pipe, especially in a newer home, probably was brought to you by a black poly pipe - not such a good ground conductor, even if the house is plumbed in copper...

[ttpete]

Originally Posted by rapidoxidationman

That cold water pipe, especially in a newer home, probably was brought to you by a black poly pipe - not such a good ground conductor, even if the house is plumbed in copper...

I'm sure it's metal in that old house mentioned in the thread.