Surge protection on old 2 wire outlets

[sxg6]

Where I live, one of the previous owners replaced some older 2 prong outlets with 3 prong outlets, but there is no equipment ground. The wire going to the outlets only has 2 wires.

I've read that surge protectors won't be able to do their job without the equipment ground. Is there any way to protect electronic devices hooked up to these outlets? I know there are whole house surge protectors, and the option to rewire, but I'm hoping there is something easier I can buy or DIY.

 

[Oldtom]

Wow, this is really unsafe and a possible fatal shock hazard. Maybe look into running a ground wire or ground it to the outlet box itself, if possible.

As an example of what CAN happen, many years ago I worked in a factory built in the very early 1900's. The outlets in the place were ancient 2 wire outlets. Our so called "maintenance man" installed a soda machine by cutting the ground prong off the 3 wire plug and filing the plug to fit the 2 wire outlet. I went to get a soda and found quarters conduct electricity really well it did not kill me, as I was only 30 and pretty fit. I complained about the "maintenance man" but management did not care :-(

The ground prong is your friend, it keeps you from becoming part of the circuit!

I am not sure about the surge protector needing a ground.

 

[eljefino]

See if there's continuity between the outlet's screw or the ground prong and "neutral."

A test light like

https://www.amazon.com/Power-Gear-3-Wire...s=outlet+tester

will show. If you have a ground the surge protector will work.

 

[knerml]

If you can run a copper wire from the outlet to a copper water pipe, you can ground it.

 

[JHZR2]

Originally Posted By: knerml
If you can run a copper wire from the outlet to a copper water pipe, you can ground it.


+1, this would work, though if youre going through that difficulty, and can reach water pipes in the basement, running new Romex may be better/safer and not that much more difficult.

GFCIs are prudent, even in two wire systems. They may not let a surge protector divert surge voltages to the ground conductor, but in the case of mismatch of current flow, they will cut it out, preventing electrocution.

 

[Mr Nice]

Originally Posted By: knerml
If you can run a copper wire from the outlet to a copper water pipe, you can ground it.


That's what I was also thinking.


It would be interesting to measure the leakage current of soda machine with analyzer.

 

[andyd]

Uhhm the way the 2 prongs worked was either knob and tube or metallic sheathed cable that when properly installed to the outlet box created a ground path. providing the other end of the sheathing was grounded. Use a continuity tester. The long hole should have continuity to to the mounting screw like Elj says. If this is going to a fuse box. You may want to start budgeting for an update How old is the house?

 

[Darkfire]

Originally Posted By: sxg6
Where I live, one of the previous owners replaced some older 2 prong outlets with 3 prong outlets, but there is no equipment ground. The wire going to the outlets only has 2 wires.

I've read that surge protectors won't be able to do their job without the equipment ground. Is there any way to protect electronic devices hooked up to these outlets? I know there are whole house surge protectors, and the option to rewire, but I'm hoping there is something easier I can buy or DIY.

The equipment grounding conductor was never a viable path for shunting surge energy to *at the point of use*, MOV (metal oxide varistor) based "protection" was genius pure marketing, not backed up by the actual facts. MOV's were never originally designed to be used in such a manner to begin with. The only place that surge energy can be diverted to ground is at the service entrance panel, for the express reason of impedance. Surge energy is high frequency, especially surges induced from nearby (not direct, we're not talking about direct strikes here) lightning strikes, where most of that energy is around 1 Mhz.

What this means is that the principal factor of impedance in relation to surge/spike enrgy is conductor length, as opposed to conductor size. The distance from your grounding electrode conductor to your grounding electrodes off your your panel is far shorter than the distance of the knob-and tube, Romex, etc is from your panel to your wall outlet. For this very reason, the National Electrical Code states that conductor leads from a surge protection device at the service entrance are to be as short as possible (leads longer than 6" start to defeat the purpose of the panel mounted protector).

Only about 15% of surge events originate from outside of a building, the main source of them is internal switching on and off of motors, like furnace fans, refrigerator, air conditioners. High frequency noise is also significantly impressed back onto all of your house wiring from non-linear loads, all those wall-wart SMPS (switch mode power supplies) that digital electronics inherently does via rectification of AC to DC. This high frequency noise is damaging by itself, degrading electronics over time, and making it more susceptible to higher energy spikes when they do occur.

Any surge energy that would make it to your wall outlet on the phase conductor (hot) is going to ignore being "shunted to ground" all the way back tens of feet supposedly to your ground rods, and water pipe if you are using that as one of your grounding electrode conductors. Instead it will see all those signal grounds of your data cables, HDMI, Coax, RCA, headphone jacks, USB, because those are part of the grounding electrode conductor at the wall outlet when you have this 3rd wire (required for *new installations* many decades now yes, but this is for safety only, not for protection of electronics, also not everyone has around $20,000.00 in cash laying around to pay an electrical contractor to rip all your old wiring out and put new romex in)).

Surge energy sees those as parallel paths. Remember electricity does not expressly "follow the path of least resistance", rather it takes *all* available paths including the path of least resistance. This means that your typical big box store suppressor is actually doing the complete opposite of what you want to do. It will cause damage by sending that surge energy right back into your connected equipment, as oppose to the physical Earth.

There is really only one way to protect equipment at the wall outlet, and that is to use a series-mode device that does not shunt energy to the EGC. You can read about how this technology works below. Note these units are far more expensive than what most people might be willing to spend, but they do in fact work, I have used them for 16 years, I have 5 units using such technology. Surgex is even better than Zerosurge because they have additional EMI/RFI filtering that is patented. These units are so robust that they are still great investments even when bought in the used market, where you can get them much cheaper than retail.

https://zerosurge.com/pq-filter/
http://espsurgex.com/surgex/

 

[kschachn]

Originally Posted By: andyd
Uhhm the way the 2 prongs worked was either knob and tube or metallic sheathed cable that when properly installed to the outlet box created a ground path. providing the other end of the sheathing was grounded.

Just the metallic sheathed cable though, not knob and tube.

 

[sxg6]

Thank you very much for the replies, I plan to read them more thoroughly tonight when I have more time.

For now, I just wanted to provide a little extra information.

I did replace one of these outlets a few months ago, since the old receptacle was worn and plugs did not feel snug at all.

Here are some pictures of the wires that I took back then, it seems to me like it's "tinned copper". The junction box picture is what the wire sheathing looks like from the outside, just plain black.

There is evidence that the house did have knob and tube at one point, but it doesn't have knob and tube anymore.

 

[dishdude]

If it were my house, I would be looking at rewiring it. Has the panel been updated? They make whole house sure protectors that go at the panel.

 

[bmwpowere36m3]

Originally Posted By: dishdude
If it were my house, I would be looking at rewiring it. Has the panel been updated? They make whole house sure protectors that go at the panel.


+1

Looks like early cloth covered romex, no ground, going into the junction box. You want to see modern romex:

or bx:

 

[sxg6]

So just to answer a few of the questions..

The house is from the 1920's, though I think there was an addition and garage put on in the 70's. There are 3-4 different types of electrical wire installed. The oldest cable what I have pictured above. After that, there is grey cloth covered cable with a ground wire going to some parts of the house, except for some reason they kept the original 2 prong outlets in, and just connected the ground to the box. The garage, and a few outlets in the house have newer romex going to them, not sure how old, but but 80's or newer.

I have a 3 prong tester, and the outlets in question say "open ground" when I plug the tester into them.

I have thought about gfci's, but I don't know if I can just replace each outlet with a gfci, or if that' stupid. The research I've done suggests that's stupid, and a rookie thing to do based off the way gfci's work.

The panel is on the newer side, not sure how old. I would say 80's or newer, 100 amp.

I think the best thing to do is obviously rewire, but not sure how much that would cost. A whole house surge protector seems like a good idea no matter what I do. If the rewire sounds too expensive, running grounds up for the basement is something I'll look into.

Thanks again for the replies.

 

[westom]

Originally Posted By: sxg6
I think the best thing to do is obviously rewire, but not sure how much that would cost. A whole house surge protector seems like a good idea no matter what I do.

Third prong on a receptacle does nothing to make power strip protector effective. Darkfire's first paragraph accurate demonstrates why - including the pure marketing genius that has even fooled some others here. That third prong is safety ground (also called equipment ground) - to protect human life. Its connection is too long, has too many splices, has too many sharp bends, etc to effectively connect to a completely different ground - earth ground.

Plug-in protectors are effective only if used in conjunction with a properly earthed 'whole house' protector. Note the most critical phrase in that sentence: "properly earthed". Since earthing (not the protector) does protection. Since protection is always defined by the quality of and connection to single point earth ground.

No receptacle must be grounded to a cold water pipe. Ground connection to pipes is a major human safety violation. Others did not suggest this, but, receptacle safety ground also must not connect to an earth ground electrode. That safety ground wire must connect back to a ground bus in a main breaker box. No exceptions.

GFCIs are an only other alternative to upgrade that two wire circuit. Any three prong receptacle powered by a GFCI and only two wires must also have a "No Equipment Ground" label on it.

Also be aware: that circuit tester can only report defects. It can never say a receptacle is properly wired. It can only report bad; cannot report good.

For human safety, a (safety ground) third prong must connect directly to the mains box. For appliance safety, a 'whole house' protector must connect low impedance (ie less than 10 feet) to earth ground electrodes. A 'whole house' protector is essential to even protect those near zero joule, power strip protectors. If a 'whole house' solution does not exist, then power strip protectors may even compromise superior protection that is routinely inside all appliances.