Moving into an old house, lack of 3 prong outlets

[jim302]

Originally Posted By: JHZR2

So the question comes to WHY YOU need a ground, as a computer buff - electronics or general safety. A GFCI-protected grounding-type receptacle without an equipment-grounding conductor is safer than a grounding-type receptacle with an equipment-grounding conductor, but without GFCI protection. This is because the GFCI protection device will clear a ground-fault when the fault current is 5mA (+ or - 1mA), which is less than the current level necessary to cause serious electric shock or electrocution.


Agree with you there... GFCI makes it safe. Surge protectors won't work as intended, so if that is a concern a UPS could be used instead - it will switch to battery in the event of a surge that is actually harmful to the equipment.

Modern decent quality switch mode power supplies usually operate just fine anywhere between 100 and 240 VAC and are surprisingly resistant to poor power conditions. No plug in surge protector will do a thing against direct lightning strike, grounded or not... so there really isn't a ton of risk.

This is just one of the joys of an older house. There are probably far bigger issues such as a lack of insulation and leaky windows that will lead to high heating bills in the winter, which would worry me more than the ungrounded outlets.

 

[SHOZ]

You can get whole house surge suppressors.

 

[exranger06]

https://www.google.com/url?sa=t&sour...Z4mk7oojIUvuRrQ

 

[Cujet]

I have a new construction house. The Neutral and ground go to exactly the same place. Just through different wires.

The both hook directly to the ground in the breaker box.

The difference is that the ground carries no current, as it's not hooked to anything on your load. But, it is the exact same connection as the neutral.

To be accurate, the ground will only carry a fault current if insulation breakdown occurs in your electrical equipment.

It goes to the exact same place as the neutral.

In other words, if nothing is wrong with your electrical equipment, the ground is useless. Read my point below.

To make matters worse, a ground may not be hooked to anything in your equipment. I've taken apart grounded electronics and found that sometimes the ground goes to nothing, and very often goes to nothing worthwhile.

What you may not know is that many old homes with BX cable and metal gang boxes have, by default, grounded electrical boxes. Simply hooking a wire to the screw accomplishes the task.

 

[westom]

Originally Posted By: Jarlaxle
An electrician told me, after checking how it was done (not the neatest job in the world, but everything was connected properly), that officially, it's not cool...but unofficially, he saw no problem with it.
Do you know why grounding a fault that way caused harm to people in showers or bathtubs? Numerous, good, and well proven reasons say why pipes are unacceptable for safety (equipment) grounding.

Second, that is only about human safety. OP originally asked about transistor safety. GFCI is about human safety - does nothing to protect hardware. Transistor protection is about earth ground - not a safety (equipment) ground in a receptacle.

Third, overloading an extension cord was irrelevant to why extension cords are unsafe; even routed as the OP describes. Install a GFCI in the same room as the computer. Then humans are protected - transistors are not. Extension cord safety ground means a protector remains ungrounded for transistor protection. Is only grounded so a protector strip does not threaten human life.

 

[westom]

Originally Posted By: Cujet
What you may not know is that many old homes with BX cable and metal gang boxes have, by default, grounded electrical boxes.
If true, then an installed receptacle would be three wire. Even a sliver can make a receptacle box appear grounded. When it must conduct a fault current, that sliver vaporizes - leaving a human at risk of death.

They did not install a three prong receptacle because ground on that box is insufficient or reliable. You have, in essence, assumed the electricians were ignorant.

If a safety ground is not physically observed, then it does not exist or is insufficient.

One wiring technique sometimes seen in old houses was to safety ground a receptacle closest to the breaker box. Then wire all following receptacles with only two wires. Only that first (closest) receptacle was a three prong type because a sufficient safety ground existed.

But again, that is only about protecting humans - says nothing about protecting transistors.

 

[Jarlaxle]

Originally Posted By: westom
Originally Posted By: Jarlaxle
An electrician told me, after checking how it was done (not the neatest job in the world, but everything was connected properly), that officially, it's not cool...but unofficially, he saw no problem with it.
Do you know why grounding a fault that way caused harm to people in showers or bathtubs? Numerous, good, and well proven reasons say why pipes are unacceptable for safety (equipment) grounding.


Reread the post: it is not hooked to plumbing pipes. It is hooked to HEATING pipes.

 

[Cujet]

Originally Posted By: westom


They did not install a three prong receptacle because ground on that box is insufficient or reliable. You have, in essence, assumed the electricians were ignorant.


I agree that an old house with BX cable may not have a sufficiently intact ground.

But the lack of 3 prong outlets in no way reflects the capability. Electricians simply did not install 3 prong outlets years ago. It was not a common practice in homes.

 

[westom]

Originally Posted By: Jarlaxle
Reread the post: it is not hooked to plumbing pipes. It is hooked to HEATING pipes.
You should know that heating pipes make an electrical connection to water pipes. Obviously. Othewise 1) bonding to a heat pipe was not recommended and 2) served no purpose.

 

[westom]

Originally Posted By: Cujet
But the lack of 3 prong outlets in no way reflects the capability. Electricians simply did not install 3 prong outlets years ago. It was not a common practice in homes.
Electricians did not install a three prong receptacle because no safety ground wire existed. Receptacles shape and size tells the user how many conductors are in the wall and even how many amps that circuit can safely provide. Even the shape and position of each hole is a human safety message.

Replacing a two prong receptacle with a three prong is simply perverting a human's important human safety message. One never replaces that receptacle without first learning what exists in the electrical circuit. If a circuit had three conductors, then the receptacle was already a three prong type. It is a two prong receptacle because a code sufficient safety ground wire does not exist.

Code is quite clear about this. A three prong receptacle can only exist if a third (safety ground) wire exists OR by using a GFCI - as accurately detailed by others.

 

[kschachn]

Originally Posted By: westom
Replacing a two prong receptacle with a three prong is simply perverting a human's important human safety message. One never replaces that receptacle without first learning what exists in the electrical circuit. If a circuit had three conductors, then the receptacle was already a three prong type. It is a two prong receptacle because a code sufficient safety ground wire does not exist.

Code is quite clear about this. A three prong receptacle can only exist if a third (safety ground) wire exists OR by using a GFCI - as accurately detailed by others.


You don't need a third wire, if the wiring method was a metallic raceway or BX cable, a metallic box (and there is a proper ground at the service equipment) then you can ground to the box - either through a pigtail or through a self-grounding type receptacle. There's a lot of older houses wired with a combination of conduit and BX cable which can be properly wired with a 3-prong receptacle.

There's a million buildings wired metallic raceways without an isolated ground.

 

[JHZR2]

Originally Posted By: Nick R
Originally Posted By: hattaresguy
Ugh I hate old houses, I'd gut that thing and upgrade all the mechanicals. The windows are probably [censored] as well as no insulation in the walls.


Only advice I have; I have zero tolerance for old houses not up to modern standards, everything I own is new.





Since we are renting, this isn't really an option. Downtown Albany doesn't really have many newer houses, and the ones there are are far more expensive to buy, and buy extension, rent.


Thing is, that area has some really beautiful classic homes too. Far nicer in construction and design than any modern builder will create.

Too bad rentals are all about profit, so the landlord won't necessarily care.

That said, in the house we rent out, an IT guy moved in and asked specifically for some extra service added in one room. We allowed it and all was well. Happy tennants stay longer.

 

[andyd]

3 prong outlets became code about 1960 in most places. I suppose that they are allowed as long they aren't touched. Modify a circuit with a ground and it has to be replaced. There are houses in MA that still have the knob and tube wiring that has no "ground". It is perfectly legal unless modified. For that matter, lead paint and asbestos don't become a problem until interfered with either.

 

[westom]

Originally Posted By: kschachn
You don't need a third wire, if the wiring method was a metallic raceway or BX cable, a metallic box (and there is a proper ground at the service equipment) then you can ground to the box - either through a pigtail or through a self-grounding type receptacle. T
If that conduit was installed sufficient to act as a safety ground, then receptacles were already three prong. Otherwise, only two prong receptacles were used.

 

[Dan55]

Until about 15 years ago before Nyc adopted the NEC. BX was used almost exclusively (No Romex) no separate ground. And my home was absolutely wired with bx and two prong receptacles.

 

[Cujet]

Originally Posted By: westom
Electricians did not install a three prong receptacle because no safety ground wire existed. Receptacles shape and size tells the user how many conductors are in the wall and even how many amps that circuit can safely provide. Even the shape and position of each hole is a human safety message.

Replacing a two prong receptacle with a three prong is simply perverting a human's important human safety message. One never replaces that receptacle without first learning what exists in the electrical circuit. If a circuit had three conductors, then the receptacle was already a three prong type. It is a two prong receptacle because a code sufficient safety ground wire does not exist.

Code is quite clear about this. A three prong receptacle can only exist if a third (safety ground) wire exists OR by using a GFCI - as accurately detailed by others.


That is utterly untrue! There are scores of homes and buildings with legally and properly installed 3 prong outlets and no ground wire. That 3rd prong grounds to the gang box, and through that box to the "armored steel cable" , casually called BX/used to be known as BX cable.

In fact, NEC 320 still allows the use of what we call BX ( "AC" steel armored cable)

320.12 Uses Not Permitted.
Type AC cable shall not be used as follows:
(1) In theaters and similar locations, except where permitted in 518.4
(2) In motion picture studios
(3) In hazardous (classified) locations except where permitted in
a. 501.4(B), Exception
b. 502.4(B), Exception No. 1
c. 504.20
(4) Where exposed to corrosive fumes or vapors
(5) In storage battery rooms
(6) In hoistways, or on elevators or escalators, except where permitted in 620.21
(7) In commercial garages where prohibited in 511.4 and 511.7

 

[kschachn]

Originally Posted By: westom
Originally Posted By: kschachn
You don't need a third wire, if the wiring method was a metallic raceway or BX cable, a metallic box (and there is a proper ground at the service equipment) then you can ground to the box - either through a pigtail or through a self-grounding type receptacle.
If that conduit was installed sufficient to act as a safety ground, then receptacles were already three prong. Otherwise, only two prong receptacles were used.


That's complete nonsense. There were tons of homes constructed with a perfectly good grounding system (conduit to BX to steel outlet boxes) that have (or had) two-prong outlets installed.

And as long as you ensure the grounding means at the service entrance is sufficient they can easily be converted to three-prong outlets.

 

[westom]

Originally Posted By: Cujet
That is utterly untrue! There are scores of homes and buildings with legally and properly installed 3 prong outlets and no ground wire.

Please read what is written and not what you want to see. I never said anything about a ground wire. If the conduit was insitalled sufficient to be a safety ground, then a three prong receptacle was installed. If that conduit is insufficient, then only two prong receptacles are installed.

Why would anyone install two porng receptacles when safety ground exists? They don't. But many with disrespect for human life assume they know more than the electrician - then replace two prong receptacles with three.

Again, nobody said safety ground is only provided by a wire - except you. If conduit is sufficient to be a safety ground, then a three prong receptacle already exists. This poster is stating exactly what the NEC says. Please read what this poster wrote and not what you want to argue.

BTW, there are also two types of armoured (ie BX) cable. One has a ground wire inside; another does not.

As long as you ensure the armour or conduit is sufficient, then a three prong receptacle can be used. In some cases, it is not sufficient. So only two prong receptacles were used.

 

[kschachn]

Originally Posted By: westom
Why would anyone install two prong receptacles when safety ground exists? They don't. But many with disrespect for human life assume they know more than the electrician - then replace two prong receptacles with three.

Again, nobody said safety ground is only provided by a wire - except you. If conduit is sufficient to be a safety ground, then a three prong receptacle already exists. This poster is stating exactly what the NEC says. Please read what this poster wrote and not what you want to argue.

BTW, there are also two types of armoured (ie BX) cable. One has a ground wire inside; another does not.

As long as you ensure the armour or conduit is sufficient, then a three prong receptacle can be used. In some cases, it is not sufficient. So only two prong receptacles were used.


The answer is because it's 1955 and that's what they did. I've seen it a lot of times in homes that were either built or updated around that time.

And I've never seen armored cable with a separate ground wire. There's a grounding strip but no wire.

 

[Nick R]

Originally Posted By: kschachn
Originally Posted By: westom
Why would anyone install two prong receptacles when safety ground exists? They don't. But many with disrespect for human life assume they know more than the electrician - then replace two prong receptacles with three.

Again, nobody said safety ground is only provided by a wire - except you. If conduit is sufficient to be a safety ground, then a three prong receptacle already exists. This poster is stating exactly what the NEC says. Please read what this poster wrote and not what you want to argue.

BTW, there are also two types of armoured (ie BX) cable. One has a ground wire inside; another does not.

As long as you ensure the armour or conduit is sufficient, then a three prong receptacle can be used. In some cases, it is not sufficient. So only two prong receptacles were used.


The answer is because it's 1955 and that's what they did. I've seen it a lot of times in homes that were either built or updated around that time.

And I've never seen armored cable with a separate ground wire. There's a grounding strip but no wire.


Given the age of the house, I'm going to assume that the original wiring (if it hasn't been removed, and who knows at this point) is knob and tube, or heaven forbid, cloth covered. The newer outlets, I'm not sure. When I get back up there when I officially move in I'm going to investiage, because they are in-floor outlets, the wiring should be visible in the basement. Maybe I'll be able to get an idea of how the rest of the house is wired.