Old Electrical Receptacle and Ground

[redbrickhat]

I recently repaired and upgraded two old 2-prong electrical receptacles
to 3-prong. Both receptacles had 2 wires and grounded boxes.

One of the receptacles is now powered and grounded properly. The other
receptacle is powered correctly but has a weak ground -- when I used a
voltage tester, the power light was bright but the ground light
flickered.

I think that the ground fault is either between the metal cable and the
box or between the screws of the receptacle and the box. The metal bars
of the box where the receptacle screws in are very rusted and corroded.


Has anyone had similar problems with this type of weak ground in a
old-style grounded box?
Do you think trying to de-rust the box will help?


Thank you.

 

[Rich Grise]

I recently repaired and upgraded two old 2-prong electrical receptacles
to 3-prong. Both receptacles had 2 wires and grounded boxes.

One of the receptacles is now powered and grounded properly. The other
receptacle is powered correctly but has a weak ground -- when I used a
voltage tester, the power light was bright but the ground light
flickered.

I think that the ground fault is either between the metal cable and the
box or between the screws of the receptacle and the box. The metal bars
of the box where the receptacle screws in are very rusted and corroded.


Has anyone had similar problems with this type of weak ground in a
old-style grounded box?
Do you think trying to de-rust the box will help?

It'll be much easier, and probably cheaper in the long run, to just
replace the box.

Good Luck!
Rich

 

[Baron]

I recently repaired and upgraded two old 2-prong electrical receptacles
to 3-prong. Both receptacles had 2 wires and grounded boxes.

One of the receptacles is now powered and grounded properly. The other
receptacle is powered correctly but has a weak ground -- when I used a
voltage tester, the power light was bright but the ground light
flickered.

In the absence of a proper ground resistance meter, a 150 Watt light bulb is
a good test !

I think that the ground fault is either between the metal cable and the
box or between the screws of the receptacle and the box. The metal bars
of the box where the receptacle screws in are very rusted and corroded.

Just replace the box. Its not worth the time and effort !

Has anyone had similar problems with this type of weak ground in a
old-style grounded box?
Do you think trying to de-rust the box will help?

See above.

 

[Husky]

I recently repaired and upgraded two old 2-prong electrical receptacles
to 3-prong. Both receptacles had 2 wires and grounded boxes.

One of the receptacles is now powered and grounded properly. The other
receptacle is powered correctly but has a weak ground -- when I used a
voltage tester, the power light was bright but the ground light
flickered.

I think that the ground fault is either between the metal cable and the
box or between the screws of the receptacle and the box. The metal bars
of the box where the receptacle screws in are very rusted and corroded.


Has anyone had similar problems with this type of weak ground in a
old-style grounded box?
Do you think trying to de-rust the box will help?


Thank you.

Sounds to me like the reality is NEITHER is safely grounded. It doesn't
take a lot of current to light that neon, the one that flickers is
definitely not safe. The other one probably isn't either as it probably
is using a BX armor as ground. Replace the outlets with GFCIs and mark
them No Equipment Ground. You will be much safer.