This is an electronics basic noob question to be sure.
I'm moving into a place that only has two pronged (presumably ungrounded) outlets. I'm trying to figure out if I will have to go back to the stone ages or if I can run my PC's and router/firewall in this home?
My thinking is that I can replace the two pronged outlets with ground-fault circuit interrupters and then plug power strips into those.
Is this a sensible solution or am I asking to burn the house down around a fried motherboard?
If it is the later could anyone advise me on a way to work in an older home?
Sure you can run the computer. The surge supresser/power strips will not be as effective as if you had a third wire ground. YOu could install a whole house protector at the fuse/braker box. A UPS would go a long way toward protecting the computer and other electronic equipment that is plugged into it. You really need a 3 wire system for the GFI to add much protection to the electronics, and that is not going to do much either way for equipment protection.
This is a rental and tearing up the walls to add a third wire earth ground isn't an option. As I understand it the danger of running a PC off an ungrounded outlet is that any voltage leaks in an unbalanced system will try to find a place to go and a metal PC (power supply, case frame, case) are the nearest place to hang out, causing anyone who touches the case to catch the volt - not to mention frying the innards of the PC.
So sans a ground in the outlet will a GFCI protect the PC from getting fried? I thought that if there was a voltage difference between the neutral and the hot wire the GFCI would trip and shut down.
Furthermore the surge protector would be a second line of defense for the PC.
Is this correct? I'm not thinking worst case scenario here where my PC is hit by lightning or anything like that so a UPS seems over the top (read, I can't afford one).
Tearing up the walls is only for safety ground. Earth ground is another connection from breaker box to earth.
They are called shunt mode protectors. They protect by shunting (diverting, connecting) destructive transients to earth. But if no earth ground exists, then no effective protection. Furthermore, a shorter path to earth (and farther from appliances), then enhanced protection. Responsible manufacturers such as Leviton, Siemens, GE, Cutler-Hammer, Intermatic, and Square D make those more effective 'whole house' protectors. What makes them effective? Breaker box should meet and exceed post 1990 National Electrical Code earthing requirements. And all other incoming utilities should also connect to this same earthing electrode.
Notice that superior protection is provided with two wire or three wire wall receptacles. It does not care because the destructive transient is shunted to earth before getting to those wires. Notice what the plug-in protector quietly forgot to mention - earth ground.
'Whole house' protector is so effective and so inexpensive as to even be installed on pone lines. But again, that protector will only be effective if also connected 'less than 10 feet' to the same earth ground that also conforms to post 1990 code.
Earthing is your line of defense. Each layer of protection is defined by earthing and how each utility wire connects to earth (ie via the 'whole house' protector). Above defines secondary protection. Primary protection should also be inspected:
I think I understand what you are asking now. Without the ground wire going to the case, a short from the hot wire to the case could be dangerous to you. Unless there is a current unbalance such as if you have the router/cable modem connected to the earth by the coax comming into it, the GFCI will not trip to save the computer as the current going out the hot wire is the same as the current comming back down the neutral wire. The GFCI will protect you if the hot wire shorts to the case and you touch the case while you are grounded.
So now I am more confused. I thought that two pronged outlets were ungrounded. But you say that they might be grounded; either through an earth ground at the breaker box or some other form of ground fault circuit interrupter at the breaker box.
How do I tell if these two pronged outlets are in fact grounded and if they are how should I best plug in a PC or a surge protector - by replacing the outlet with...What? If there isn't a ground wire running through the walls putting in a regular three pronged outlet would be useless, except that the PC power cable would fit.
1) The operation of a GFCI does not depend on the GFCI being connected to ground.
2) A GFCI is intended to protect people, not equipment. It is used for *your* safety, not the safety of the attached equipment.
3) The installation of a GFCI receptacle on an ungrounded circuit is permitted, and is a good way to enable the use of 3 prong plugs. It does not provide the same electrical function as grounding.
I thought that if there was a voltage difference between the
No - if there is a *current* difference greater than ~ 5mA the GFCI will trip. There is always a voltage difference between neutral and hot of ~ 120 volts (in the US) in a properly operating circuit.
You seem to think the GFCI is a first line of defense for the PC - that is wrong. The GFCI provides no defense for the PC - it allows you to plug in the 3 wire PC cord, and protects you from a fault current should the PC case become electrically "hot".
And since it is an apartment, you can't put in a whole house surger protector or re-wire. So the only thing you can do for PC protection is install point of use surge protectors.
I never said those wall receptacles are grounded. I said, to have an effective protector, the breaker box must be earthed so that a 'whole house' protector has an earth ground. An earth ground, not to be confused with safety ground that does not exist in two wire receptacles.
To protect appliances from being fried (from transients), breaker box must be earthed. Then a 'whole house' protector will have an earthed connection so that computer, et al is not fried. Surge protectors earth a transient. Obviously wall receptacles have no ground whatsoever. Therefore how can they earth transients? They cannot.
Ground fault interrupter was implied as a type of ground. It is not. GFCI is for human safety and can provide that safety even if safety ground does not exist in that wall receptacle. Notice a difference between safety ground and earth ground; and different functions of those grounds: human safety and transistor safety. Function of a safety ground is human safety. But a GFCI without safety ground may also provide that function.
The only way to convert a wall receptacle to three prong is to either route a ground wire to that receptacle OR install a GFCI (with appropriate warning label that says No Equipment Ground).
GFCI (like fuses) does noth> So now I am more confused.
So without the whole house protector (the ground wire running through the house to each outlet) There is no way to achieve computer or transister protection. Correct?
Again wire running to wall receptacles has no relationship - is irrelevant to - a 'whole house' protection system. There is a protector. Where is it located? At breaker box. OK. A shunt mode protector needs a short connection to earth. Fine. Post 1990 NEC requires an earthing connection adjacent to breaker box. Now that protector is earthed - is made effective.
What does a shunt mode protectors do? It either connects a transient to earth or it provides ineffective protection. Do you have earthing wires in wall receptacles? No. Is that earthing connection short (ie 'less than 10 feet'). No. Two reasons why shunt mode protector are ineffective when plugged into wall receptacles.
There are series mode protectors. But again, that means building earthing must be upgreaded to post 1990 code requirements. Even if wall receptacles remain two wire, still, effective protection even using series mode protectors means earthing at service entrance must be upgrade. Must meet and exceed post 1990 requirements AND all other incoming utilities must also connect short (ie 'less than 10 foot') to that same earth ground.
Earthing is where all transient protection starts. Does this exactly answer your question? No, because your question is chock full of assumptions. However where do you start with electronics protection? Earthing. Don't worry about interior wires for transient protection. Transient protection is where utilities enter a building (secondary protection) AND where utility also earths (primary protection as demonstrated in
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citation).
The other issues > So without the whole house protector (the ground wire running through
That is what w_tom says, but the IEEE and the NIST both say plug-in surge protectors are effective.
The best information I have seen on surge protection is at
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- w_tom provided the link to this guide
- the title is "How to protect your house and its contents from lightning: IEEE guide for surge protection of equipment connected to AC power and communication circuits"
- it was published by the IEEE in 2005
- the IEEE is the dominant organization of electrical and electronic engineers in the US
- the 5 authors have broad experience with surge suppression
Another reference is
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- this is the "NIST recommended practice guide: Surges Happen!: how to protect the appliances in your home"
- it is published by the National Institute of Standards and Technology, the US government agency formerly called the Bureau of Standards
- it was published in 2001
- it was writen by Francois Martzloff - the NIST guru on surges and lightning
Both guides were intended for wide distribution to the general public to explain surges and how to protect against them. The IEEE guide was targeted at people who have some (not much) technical background.
Both say plug-in surge suppressors are effective.
Plug-in surge suppressors clamp the voltage between the wires. Earthing is secondary. This is clearly described in the IEEE guide. Without a ground wire, some earthing will still occur on the neutral back to the service panel. Not desirable, but you work with what you have or change it. As ehsjr said "the only thing you can do for PC protection is install point of use surge protectors". With no ground you still need a GFCI.
A phone line connection to a computer can be a surge entry point if the ground reference between the power connection and the phone diverge. The best solution is a surge reference equalizer, described in the IEEE guide (multi-port protector in NIST). These would be unwise without a power ground wire. Unplugging the phone line when not in use would be a good idea. Or unplug phone AND power.
IEEE and NIST 'introduce' various types of protectors. A plug-in protector may be effective IF all six ports area integrated into 'SRE protection'. You don't know what SRE is? Important if plug-in protector is to be effective. But another fact that Bud would have you believe you need not know.
Details in Bud's citations demonstrate again and again why plug-in protectors don't provide effective protection. For example, two TVs at
8000 volts because a transient was not earthed? Somehow that will never create damage? Nonsense. Instead everything in that room must be part of a faraday cage so that 8000 volts is not destructive. Do you know how to reconstruct a room to be a faraday cage? If so, then the plug-in protector could be effective. Show me a layman who knows how to reconstruct each room to be a faraday cage? Bud may call that effective. But I call a protector that requires room reconstruction and advanced engineering knowledge to be ineffective. Ineffective especially since those same dollar bills can install the effective 'whole house' protector. Especially when those same dollar bills can make a 'whole house' protector even better by enhancing / expanding a critical and essential earthing system.
NIST / IEEE does not recommend as Bud assumes. Those papers define various protector methods. Those same papers also include paragraphs that define superior protection methods such as:
And this quote directly from Francois Martzloff - Bud just forgets to tell whole truths:
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Meanwhile, Bud cut and pastes this same claim everywhere. He ignores the many reasons why plug-in protectors fail - in his own citations. Some above quotes are from his citations. They demonstrate significant electrical engineering caution necessary when the plug-in protector has no short (ie 'less than 10 foot') connection to earth.
They are called shunt mode protectors. They are effective when they shunt the surge into earth. So plug-in protector manufacturers don't discuss earthing. You might learn why those plug-in protectors are not effective. They don't even claim to provide protection from typically destructive surges in their own numerical specs. Why would they be effective when even the manufacturer does not make that claim? Bud knows why. It's in is own IEEE / NIST citations that also demonstrate why plug-in protectors are not effective; can even contribute to damage of the adjacent appliance.
Effective protection earths before those destructive transients can enter the building. That also defined by Bud's own citations.
Meanwhile effective protectors are sold by more resp> That is what w_tom says, but the IEEE and the NIST both say plug-in
"SPECIFIC PROTECTION EXAMPLES "The previous sections have shown, in general, how to protect electronic systems in houses: "1) Proper grounding and bonding, especially at the service entrance. "2) AC panel and primary signal surge protection at or near the service entrance. "3) Multi-port plug-in protectors near the equipment to be protected." #3 explicitly recognizes plug-in surge suppressors as effective. As is clearly described, these devices work primarily by clamping all wires to a common ground at the surge suppressor.
Why do both examples of surge protection in this chapter use multi-port plug-in surge suppressors?? If you have trouble figuring out the text look at the nice pictures of multi-port plug-in surge suppressors.
---------------------- NIST guide
page 12 discussing protection of 2-port equipment: "A simple solution to the problems of voltage differences for two-link appliances is to install a special surge protector that incorporates, in the same package, a combination fo input/output connections for the two systems. Each link, power and communications, is fed through the protector which is then inserted between the wall receptacles and the input of the appliance [electronic device] to be protected. This type of surge protector is readily available in computer and electronics stores, and the electrical section of home building stores." If you have trouble figuring out the text look at the nice pictures of multi-port plug-in surge suppressors.
page 16 - questions and answers: "Q - Will a surge suppressor installed at the service entrance be sufficient for the whole house? "A - There are two answers to that question: Yes for one-link appliances [electronic devices], No for two-link appliances. Since most homes today have some kind of two-link appliances, the prudent answer to the question would be No - but that does not mean that a surge protector installed at the service entrance is useless. ...."
Page 17 - surge suppressor installation hints: "Plug-in (with cord or directly into receptacle) The easiest of all for anyone to do. The only question is "Which to choose?"
------------- Another paper writen by Martzloff, the NIST guru on surges, describes surge reference equalizers.
"CONCLUSIONS "The rapid expansion of smart electronics involving power and communications connections creates the potential for disappointing performance under surge conditions if adequate, coordinated protection is not provided. Separate, uncoordinated surge protection of each of the two ports still leaves the possibility of damage or upset. "A new type of device, the 'Surge Reference Equalizer', offers a solution to the problem, provided that the performance characteristics of the device will be coordinated with the environmental stress and with other surge-protective devices that may be installed on the systems."
----------------------------- It takes willfull stupidity to claim the IEEE guide, the NIST guide, and Martzloff do not say plug-in protectors are effective.
They do not operate primarily in shunt mode. The IEEE guide clearly describes, to anyone who can read and think, the action as clamping wires to a common ground at the plug-in surge suppressors. Your reading/thinking disability is unfortunate.
The IEEE and NIST guides clearly say plug-in surge suppressors are effective.
And you have never provided a link to a reputble source that says plug-in suppressors are not effective. It is you against the world.
And then we add missing parts to that sentence, that Bud routinely forgets. He misrepresents IEEE papers. 'Effective' if one with advanced technical knowledge can carefully eliminate all six ports of failure in that room - construct a farady cage. The six ports as described in Bud's SRE paper. And what is found in conventional rooms? Items and materials that violate those six ports - compromise protection as defined by that IEEE paper. Any one of the six ports makes an adjacent plug-in protector ineffective as detailed in those IEEE papers.
That and other papers cited by Bud note, a plug-in protector can contribute to damage of an adjacent appliance: "even when or perhaps because, surge protective devices are" adjacent to that appliance. Why does he repeatedly ignore that conclusion from his own citations? Who does he represent?
"High-current surges ... are best diverted at the service entrance of the premises." - also from Bud's own citations.
What does another citation define as an effective protector?
His company's products don't have that earthing wire.
Others are encouraged to locate claimed protection in numerical specifications for a plug-in protector. Such numbers do not exist. They don't even define protection for each type of transient? Why? Ask what Bud hopes you don't ask. Ask why a surge that seeks earth ground destructively via an appliance is not listed in those numerical specs? Why mention a transient that plug-in protectors don't protect from? No earth ground means no effective protection. They are shunt mode protectors - only as effective as their earth ground. Earth ground? Plug-in protectors don't even discuss earthing in a hope that you don't ask such embarrassing questions.
If you could read and think you could see the point of the SRE paper is that SREs protect the six ports:
"The surge reference equalizer combines the protective function for both system ports in the same enclosure. A common, single grounding connection equalizes the voltages of the two paths that return the surge through the grounding connection of the 3-prong power line plug... Such a solution is particularly attractive as an element of 'whole-house protection'..."
Apparently you can't argue on the science. I have no interests in surge suppressors.
Stated numerous times and clear from the IEEE guide: plug-in surge suppressors work by clamping wires to the common ground at the surge suppressor. They work primarily by clamping, not earthing. It is embarrassing you can't read the description - clamping is the primary protection.
The IEEE and NIST guides clearly say plug-in surge suppressors are effective.
You have still never provided a link to a reputble source that says plug-in suppressors are not effective. No one agrees with you.
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