Weird Electrical Experience

[jviss]

Bought a house that was built in 1925. All of the original electrical outlets are set horizontally into the baseboards, but there are a couple of new ones in the wall, more as it's done these days.

I got a cable modem WiFi gateway from Xfinity, and once I had connected the cable, plugged it into the new power outlet. Nothing! So, I moved it to one of the old outlets and it worked.

Then I got my outlet tester and found the new outlet has neutral and hot reversed.

So, would the router detect this and refuse to power up? Maybe the coax was grounded and some interaction with the power cord prevent powering up?

Would love to know.

Thanks,

jv

 

[rgranger]

If there was a rectifier (diod) bridge in the power lead that converts the AC to DS... that would explain why it didn't power up.

 

[Stu Jackson]

Remember the old days when it didn't matter which direction you plugged a two prong A.C. plug into a receptacle? Before the ground plug was added and before the larger prong was introduced?

 

[rgranger]

 

[Johnb]

You don't say whether anything else worked on that outlet but, if the live wire was on the receptacle where the neutral should be AND the neutral on the receptacle was not connected at all, but the ground on the receptacle was connected to either the neutral or ground wire, THEN the tester would show live and neutral reversed but no appliance would work.

 

[Davidasailor26]

So, would the router detect this and refuse to power up? Maybe the coax was grounded and some interaction with the power cord prevent powering up?

I like that theory. The modem probably just steps the AC down and rectifies it, so the polarity wouldn’t really matter for that. But maybe there’s some circuitry in the modem that bonds the coax ground to neutral, and has some safety preventing anything from connecting if the polarity is reversed.

Having said that, a quick Google doesn’t show any similar stories, so maybe not.

 

[LloydB]

Not weird. Wrong. Call the inspector/electrician back to your new to you to you house. Better to fix it now than find out later. On the other hand should have worked anyway if not just a tripped GFI just my opinion.

 

[jviss]

Not weird. Wrong. Call the inspector/electrician back to your new to you to you house. Better to fix it now than find out later. On the other hand should have worked anyway if not just a tripped GFI just my opinion.

Yea, the weirdness is the router/gateway. wouldn't power up; the vacuum was just fine with it.

I know how to correct it, I will when I get a chance. I just hope they swapped it at the wall device, it would be truly weird if the swapped it in the electrical panel!

 

[Leeward Rail]

Grounds where not required in 1925 and cords didn't have polarized plugs. I have seen houses where the wires were reversed after someone installed newer outlets. Not surprising at all. Especially when the homeowner is doing the work.

FWIW grounds really started being mandated around the early 60s.

Would be interesting to tear down the router power supply.

Edit: I used to carry a tester around in the 80s after I got zapped when using a microphone plugged into one amplifier , while playing a guitar plugged into another.

 

[jviss]

Grounds where not required in 1925 and cords didn't have polarized plugs. I have seen houses where the wires were reversed after someone installed newer outlets. Not surprising at all. Especially when the homeowner is doing the work.

FWIW grounds really started being mandated around the early 60s.

That's very interesting, thanks. My house's original outlets are boxes that are horizontal, in the baseboards. But, they have been upgraded with three prong, polarized receptacles, that are wired correctly. The house's wiring is BX (armored) cable.

Would be interesting to tear down the router power supply.

Yes, it would!

Edit: I used to carry a tester around in the 80s after I got zapped when using a microphone plugged into one amplifier , while playing a guitar plugged into another.

That's actually quite common.

 

[All U Get]

I had all my outlets polarity checked since a few didn’t conform just to make Alexa happy.

 

[WayneH]

When I bought my first home, there were two breakers in the panel that would fight each other. Reset one breaker and the other one would trip and vice versa. I should have had it looked at but everything was working so I just let it ride. Fast forward 5 years and the built in gas oven failed. When I pulled the old oven out, I discovered two receptacles in the wall behind it, one about 6 inches above the other. And yes, there was a jumper wire between the two. Once I removed the jumper, the two breakers would reset and not trip each other.

Amazingly, the house is still standing 40 years later.

 

[rgranger]

I once worked in a new science building and the breakers would trip every time we had an electical storm. After a few months we realized the breakers were installed backwards. Go with the lowest bid and you get what you payed for.

 

[RoyS]

In old houses with questionable wiring you might want to try installing arc fault and ground fault circuit breakers. These may point you to circuits needing attention. Lighting circuits with old bx wiring can be a real problem. It is common to find the original rubber insulation has dried up and is falling off inside boxes over fishbowl lights, particularly in kitchens. Consider removing your sagging plaster ceilings and rewiring all.

 

[jviss]

Consider removing your sagging plaster ceilings and rewiring all.

Hey, Roy, just bored and strolling down Sails Call memory lane here, and saw this. Are you kidding? Ha, ha. My plaster ceilings aren't sagging, at all. This house was really built, and built well. But are you really suggesting I rewire "all," that is, the whole house? Wow.

 

[RoyS]

I worked on many old houses around here. Often, going hand in hand, were horse hair plaster with wooden laths and BX wiring. Typically I would find a 1920 fishbowl type light fixture with two 100 Watt lamps lighting an entire kitchen. Removing the fixture would reveal a 3" octagon metal junction box packed with old BX wiring with soldered splices, each covered with friction tape. If I tried to move any of the wires the insulation would fall off exposing the bare copper conductors. This was due to the old fishbowl lighting fixture baking the wiring above it for the last 100 years. Further, returning to our kitchen example, there would be one 15 Amp circuit (fused with a 30 Amp Fuse) going to the light fixture with every receptacle outlet in the kitchen tapped off of that. There was always a window air conditioner in the circuit as well. The ceiling would be sagging with the brittle plaster long separated from the laths in many places. In such cases I would suggest tearing down all the ceilings and totally rewiring the entire house. The walls might remain with new wall wiring fished in. My suggestion was never well received by some home owner standing by hopefully with their "new" home depot track light in their hands. A lot has happened electrically in the last hundred years and the horses are all gone. Don't shoot the messenger. And don't drive the Model T on the highway either.

 

[jviss]

Thanks @RoyS , that's interesting. Yes, I have BX wiring as original. The small fuse box was removed at some point and a 200A, 40 circuit panel installed in the basement, and all of the old circuits patched down to that panel, patched where the old fuse box was; the "box" enclosing the older fuse box remains. All of the new wiring is Romex.

Yes, indeed, I took down a flakey original ceiling fixture in the rear entrance hall and the cloth insulated wires from the BX are in tough shape. This one's in spitting distance of the old box, so I might just rewire to it.

But the plaster in the entire house is in beautiful condition, as I said, no sags anywhere.

My thoughts on the old wiring is leave well enough alone. The house is big and complicated, and to pay to rewire it I'd have to sell it!

 

[RoyS]

My own house was built in 1930. The plaster was a rock lath system and is very sound. I have plenty of old BX wiring still in use, mostly in the bedroom walls. Could have been worse, some of my neighbor's houses have knob and tube wiring. I once was called to work on a house in Boston. Two women had bought it together and moved in. They quickly realized that the electrical wiring was inadequate and called me to make a few upgrades. That was the only time I saw a still functioning 120 Volt, 30 Amp service. There were two glass Edison base fuses, a single thirty Amp main and a single fifteen Amp for everything after that (one circuit). Each room had either a porcelain pull chain lamp holder or a single receptacle, never both. They had a report from the "Home Inspector" from when they bought the house a few months earlier. I asked to see it. There was absolutely no mention of electrical wiring in the "Home Inspection Report". Very unhappy campers there after talking to me. We should switch to PM's before we are shown the door.

 

[jviss]

We should switch to PM's before we are shown the door.

Well, this is "Sails Call," so I think any topic is fair game, no?

Too bad about those sisters! My first house was 1947, BX cable, with a 6 circuit, 60 Amp service (glass, screw-in fuses). I immediately upgraded to 200A 40 circuit with the help of my neighbor, a licensed electrician. That was a great learning experience.

 

[rgranger]

Well, this is "Sails Call," so I think any topic is fair game, no?

I think so... except maybe politics and religion but I could be wrong about that.