House Power and Outlet question.

[westom]

But I'm not sure that will satisfy the requirements of the surge suppressor. GFCIs are for people. I just don't know enough about how the suppressor shunts over voltage to the ground at the outlet to say if the GFCI is all it needs.

GFCI is how to get human safety without any safety ground. Safety ground is also called equipment ground. It is completely different from earth ground.

Effective protectors work by connecting tens of thousands of amps on a low impedance (ie less than 10 feet) wire to earth ground. Then hundreds of thousands of joules harmlessly dissipate outside; do not dissipate destructively inside appliances. Protectors without earth ground (ie his power strips) do not claim to protect from surges that typically do damage. Those have all but no earth ground if used on two wire or three wire receptacles. But surge protector strips can become dangerous to human life if not connected to a safety ground.

Meanwhile, best surge protection for all three wire houses is also best protection for two wire (pre-1960) homes. That is one properly earthed 'whole house' protector. Then hundreds of thousands of joules harmlessly dissipate outside. Then his computer and power strip protector are protected from surges that can actually do damage. And that, in rare cases, can result in a protector generated fire.

'Whole house' is the only solution always found in facilities that cannot have damage. It costs about $1 per protected appliance. Or can be rented from an electric company that installs it behind their meter.

Protection is defined by the quality of and connection to earth ground.

 

[frowertr]

Effective protectors work by connecting tens of thousands of amps on a low impedance (ie less than 10 feet) wire to earth ground. Then hundreds of thousands of joules harmlessly dissipate outside; do not dissipate destructively inside appliances. Protectors without earth ground (ie his power strips) do not claim to protect from surges that typically do damage. Those have all but no earth ground if used on two wire or three wire receptacles. But surge protector strips can become dangerous to human life if not connected to a safety ground.

This was my point. Installing the GFCI just gives you a 'safety ground" but it won't do anything to actually protect your equipment from a surge. You need an 'earth ground' to do this as the rest of your post suggest.

You're right, though, about a whole house protector. That could be installed in the main breaker box (or on the outside disconnect panel if there is one). I have one of these in my home connected to my outside disconnect panel. In lieu of that, a new 3 conductor branch would be the best step to satisfy the earth ground. Both of these options are of magnitudes cheaper than an electrical overhaul to the entire home.

 

[bruceb]

When BX was introduced there was no requirement for a seperate ground wire. And I think the currrent NEC does not require one if BX / Armored cable is used with metal boxes. Of course if you want to use 3 wire armored cable (white, black, green) like Home Depot sells, it is usually an Aluminum clad cable, not steel like the old style BX cables.

http://www.mikeholt.com/forum/forum1/html/002081.html

[FONT=Verdana, Arial][FONT=Verdana, Arial]Type AC, the sheath, is considered a grounding conductor 250-91(b). The alum. type you speak of is MC. Generally supplied MC is not considered a grounding conductor.
Thus the supplied grounding conductor. Not sure why they feel MC isnt a suitable grounding conductor other then it could become seperated more readily then the AC. [/FONT][/FONT]

 

[westom]

When BX was introduced there was no requirement for a seperate ground wire. And I think the currrent NEC does not require one if BX / Armored cable is used with metal boxes.

When we built an early 1960s home, all wire was BX. BX to three prong receptacles (ie kitchen) had a ground wire included. Other BX (ie that connected to bedrooms) had no internal ground wire. So those receptacles could only be two prong. Those had to be two prong because that BX connection was mechanically unreliable.

Back then, a ground wire was connected to a screw inside that metal box. Ground prong connected via a receptacle's mounting screws. History determined those mounting screws also were insufficient. So code was upgraded to require a receptacle be hardwired to that BX ground wire. Again, this is all about human safety. A ground connection must be reliable.

Many claim a receptacle can be replaced with a three prong only because a ground connection is electrically detected. What may be detected by a meter is still insufficient because that connection is not mechanically reliable.

Safety ground is completely unrelated to the OP's concerns.

OP's anomaly was only speculated to be a receptacle. But a UPS would have made that anomaly completely irrelevant. Numbers make possible a better reply. UPS is (apparently) three years old. Battery life expectancy is typically 3 years.

Only reliable UPS battery test is as redzo discusses. Literally power a computer from a UPS that is disconnected from AC mains. To measure how long that UPS battery can provide power.

Is AC power an issue? An effective test is easy. An incandescent bulb powered from the same source should not change intensity even when other major appliances power cycle. Meanwhile, ideal voltage for a computer is anywhere from 40% dimmed to twice as bright. If your electricity varies even that much, then a potential human safety issue exists with household wiring. Do not cure that symptom with a UPS. Locate and correct that wiring defect.

 

[bruceb]

Old electrical circuit panels, be they fuse or circuit breaker type do go bad. All it takes is some oxidation or wires slightly loosening up. I did a job once where the owner tried to change out a switch and then lost power to like half a floor. It was tracked down to a bad multiple wire connection in that junction box. Undid the wire nut, cleaned up the wire, and redid the connection. Everything then worked as it should.

 

[kalmquist]

What is likely happening is as mentioned one outlet (the one with 4 wires) is feeding the other one (by your computer). I would almost bet on a bad connection at the 4 wire outlet. You have an old house and the outlets are probably the originals. Replace both of them with new ones and be sure all the wires, especially where one feeds the other one are nice and clean. You can either restrip the wire if it is long enough or just use a piece of sandpaper to polish the copper before you reconnect it. Could also be a bad circuit breaker or loose wire at the main panel. Especially check the Neutral at the panel.

That sounds like good advice. The one thing I would add is that he should check whether the wiring is copper or aluminum. If its aluminum, he should buy outlets which are approved for aluminum wiring. Typically these will be labelled CO/ALR, meaning that they can be used with either copper or aluminum

 

[Tarvaln]

So, I replaced the outlets, check the wire which are copper, then sanded or stripped all of them.

I'm still confused about the grounded issue. Do these need to be grounded for my UPS/PC?

 

[bruceb]

The UPS probably does not care if grounded or not. But your computer should be grounded, so the outlet feeding it should also be. Good safety and also better for sensitive electronics.

 

[frowertr]

Yes, it needs an earth ground to be able to act as a surge suppressor. It has to shunt the over voltage 'somewhere'. The 'somewhere' is the ground.

The earth ground isn't required for the battery backup portion to kick in.

 

[MrTeal]

That has never been my experience. The UPS and outlet checkers I have used have always been correct when they showed a wiring fault.

Just had this happen at a friend's house in VA. UPS wiring fault light was on. Got an outlet checker, which showed a Hot/Neutral reverse. Sure enough when we tracked the wiring back, we found just that and corrected it.

The Neutral and Ground are supposed to be bonded together, aren't they? Typically at the end inside the breaker box?

In the US, anyway.

Canada (and most places in the US) use a split phase 240V system. You have the two hots and the neutral come in from the pole (or underground, depending). The neutral is tied to the earth at the transformer. Inside your house, your main panel has a grounding wire that connects to a buried plate or rod. All the grounds in your house (including sub-panels) have their grounds star out from the main ground connection.

As westom said, the ground has nothing to do with the delivery of power to a system. Ideally no current will flow at all. The fault you indicate is one that's easily tested, while some others (like connecting the ground to the neutral) can't be tested with a standard plug.

 

[LTC8K6]

Canada (and most places in the US) use a split phase 240V system. You have the two hots and the neutral come in from the pole (or underground, depending). The neutral is tied to the earth at the transformer. Inside your house, your main panel has a grounding wire that connects to a buried plate or rod. All the grounds in your house (including sub-panels) have their grounds star out from the main ground connection.

As westom said, the ground has nothing to do with the delivery of power to a system. Ideally no current will flow at all. The fault you indicate is one that's easily tested, while some others (like connecting the ground to the neutral) can't be tested with a standard plug.

Right, there is only current there when there is a fault somewhere.

With power shut off, there should be continuity between the neutral and ground terminals at each outlet, because they are bonded together way back at the beginning, where the wiring comes from.

 

[westom]

I'm still confused about the grounded issue. Do these need to be grounded for my UPS/PC?

If a receptacle connection is firm (using screws; not a backstab method), then sanding was unnecessary. Backstab type connections can be problematic for computers.

Ground only exists to protect human life. It has no useful function for hardware protection. If an appliance plug has a third prong, then it must connect to a receptacle's "safety ground" - only to protect human life. As so many others noted, safety ground has no effect on hardware operation. It is about protecting human life.

That receptacle might permit backstab connections for a black (hot) and a white (neutral) wire. But safety ground is only connected via a screw. Intermittent electrical connections are permitted on black and white wires. But safety ground is so critically important (to protect human life) that only a screw connection is permitted.

Those requirements are only about human safety. But you would not want an intermittent computer crash or voltage variations (as indicated by dimming or brightening incandescent bulbs). So each wire should be firmly wrapped around and clamped by that screw.

 

[MrTeal]

Right, there is only current there when there is a fault somewhere.

With power shut off, there should be continuity between the neutral and ground terminals at each outlet, because they are bonded together way back at the beginning, where the wiring comes from.

Yup. Other than your panel (and the main earth ground at the transformer) there shouldn't be any other connections between neutral and earth ground. However that's often not the case, especially if people have old audio gear, ect. There's some bad stuff out there.

Without a milliohm meter (and an unpowered circuit) it would be pretty challenging to differentiate between a connection at the panel and a connection in the box.

 

[westom]

Without a milliohm meter (and an unpowered circuit) it would be pretty challenging to differentiate between a connection at the panel and a connection in the box.

That can be detected even using a $6 multi-meter and some robust appliance such as an electric heater, iron, vacuum cleaner, etc. Known is a ballpark distance back to a breaker box and the wire's gauge. A voltage difference appears between neutral and safety ground when a major appliance is powered. A voltage difference (ie maybe one or two volts) would appear when that appliance consumes a large current. Insufficient voltage implies a fault between neutral and safety ground.

Same fault may also be detected by a GFCI in the breaker box.

 

[MrTeal]

That can be detected even using a $6 multi-meter and some robust appliance such as an electric heater, iron, vacuum cleaner, etc. Known is a ballpark distance back to a breaker box and the wire's gauge. A voltage difference appears between neutral and safety ground when a major appliance is powered. A voltage difference (ie maybe one or two volts) would appear when that appliance consumes a large current. Insufficient voltage implies a fault between neutral and safety ground.

Same fault may also be detected by a GFCI in the breaker box.

I'm usually hesitant to suggest a homeowner stick multimeter probes into a live circuit, but you can do it that way as well.


Re: The appropriately named BS connectors, I actually just had a fairly major failure in my basement due to them. The basement was finished in the 70s, and pretty much all the plugs in it are on two breakers. A couple weeks ago half the plugs and lights on one branch died, but the others worked and the breaker didn't trip. It took me a good hour to find the stupid plug that had burned out.

Pretty much every one I saw was source into the backstab and feed out to the next one, daisy chained through the whole basement. Backstab may be code acceptable, but it's one of the worst pieces of crap in there. I wish manufacturer's would build the plugs without them.

 

[westom]

Another example of the underlying principles. Code is only about human safety. It says nothing about appliance safety or reliable operation. That 'browned' neutral wire is not a human safety issue since it would not cause a fire.

Our electricians stopped using backstab connections only years after that method existed. Less expensive was to to connect via a screw. Because one intermittent backstab connection was so expensive to locate and correct - as MrTeal demonstrated.

Code only discusses what is necessary for human protection. Exceed code requirements for reliability and appliances protection.

 

[bruceb]

They do make some receptacles where you slide the wire in and then the screw is tightened, which in turn clamps down on the wire. A wire around the screw is much better, but takes more time to do and the electrician has to make a U Loop of just the correct size to go around the screw terminal.