Ungrounded outlet, no surge protector

[MidnightOwl]

I've always used my cpap with a surge protector/power strip plugged into a grounded 3 prong outlet. Now I'm moving someplace with only 2 prong ungrounded outlets. Can I safely dispense with the surge protector and just plug the cpap machine into the outlet? Would I get some additional protection by plugging the surge protector into a 2 prong (ungrounded) adaptor? If I do without the surge protector how much risk is there to the cpap or to me?

midnightowl

[ww]

I've always used my cpap with a surge protector/power strip plugged into a grounded 3 prong outlet. Now I'm moving someplace with only 2 prong ungrounded outlets. Can I safely dispense with the surge protector and just plug the cpap machine into the outlet? Would I get some additional protection by plugging the surge protector into a 2 prong (ungrounded) adaptor? If I do without the surge protector how much risk is there to the cpap or to me?

midnightowl

CPAP machines are pretty safe due to the medical isolation provided by the power supply and non conducting hoses and masks. You are probably ok with the unit simply plugged in using the surge protector strip.

It is difficult to give advise because there are so many things to consider, but if I were in the same circumstances, I would buy a portable GFI unit that you can plug into the two wire outlet and then plug your surge protector into that. That is a good solution because it gives another layer of protection that an ungrounded outlet does not provide.

I would also find a suitable ground point such as a cold water copper or steel pipe that is directly connected/buried in the ground and run a #14 insulated ground wire from a clamp on that pipe (scraped or sanded clean of corrosion) to the grounding screw on the GFI or surge protector. If a ground is not available, usually there is a suitable ground rod at the electrical entrance panel or you can drive an 8 foot suitable ground rod in the ground near an outside wall. Although it is not essential to have both the GFI and grounded wire, it is not difficult to have both.

An electrician or any DIY guy/gal can hook this up for a few dollars and it ensures that you have all the protection that new code compliant houses have for your protection. The GFI by itself is really simple and costs only a few ($20) on a short extension cable and provides most of the same protection in your case as the added ground wire provides. GFI boxes keep you from getting shocked by a minute electrical leakage and disconnect the device plugged into it. GFI's can falsely cut off a needed device (CPAP) and be a nuisance if it happens often, although it is not likely to happen.

[Goofproof]

Depending on the quality of the Surge protector, it may still help, without being grounded it won't be as effective. A CHEAP Poor Quality Surge Protector is of little use even grounded, many have no way to test themselves, one hit and they are done, and you don't get any warning.

There is little risk to the XPAP user with or without one. When your number comes up, it's up! Jim

[timbalionguy]

It sounds to me like you are moving into an older home in a large city or perhaps New England somewhere, where lots of places existed before there was modern electric wiring.

First, the three prong issue. If your power cord is two prong, then you are OK. Safety standards for medical equipment are very high, and the lack of a ground probably indicates that the 'hot to the mains' portion of the machine is double insulated. My brand new Intellipap machine has a built-in supply, and much to my surprise only requires a two prong cord.

If your machine uses a three prong plug, or if you feel you really need surge suppression, consider consulting an electrician to see if a ground can be added to the circuit in your bedroom. Although chances of a ground fault accident are very small with quality CPAP equipment, the ground is always good safety practice.

As far as surge suppession goes, a surge suppressor is only going to be partly effective if there is a surge, lightning hit, etc if it is not grounded. It will clamp surges that occur between the hot wire and neutral (called a 'normal mode surge'), but not between hot and/or neutral and ground (called a 'common mode surge').

Most surges caused by electrical problems out on the grid are normal mode surges. I have seen some really nasty ones, including one that nearly started a piece of equipment on fire in the TV station I work at. The more inexpensive surge suppressors out there protect against this kind of fault, and do not necessarily need a ground.

Common mode surges are more likely a result of lightning. In Wisconsin where I grew up, lightning damage was far more common than utility problems. (I could always count on replacing a dozen or so rectifier diodes in TV sets at the TV repair shop I worked at, after a bad summer storm!) These need a surge suppressor connected to ground to work properly. So, if you feel lightning is going to be your biggest problem, look at getting a real ground to the outlet for your CPAP machine.

A 3 to 2 pin adaptor is only going to work properly if the box the outlet is mounted in is properly grounded. An electrician can test for this for you, or there are some ways to do it yourself. If the box is grounded, it is worth the money to have the outlet replaced with a three prong outlet that grounds to the box (This is the most common type, anyway).

I do not use a surge suppressor on my CPAP machine, but your post is making me think this through. (Although Reno is very dry, we occasionally have 'dry lightning' here which can be extremely destructive. We had one hit, centered as far as I can tell on a cage at the zoo next door. Animals inside were unharmed, as the cage shielded them from the electric field. But starting with two security cameras mounted on that cage and spreading out two residences in each direction, a total distance of more than 500 feet, everyone had lightning damage. Besides the damage to the cameras, the zoo lost a credit card machine, I lost a brand new modem, my neighbor lost a TV, etc.) My home is fairly new and the wiring is thoroughly modern.

What you really might consider is a UPS for your CPAP machine. Power outages here are quite common, enough that it is said that Reno has more generators per capita than any city in the US! Also, newer homes have what is called 'arc fault protectors' on bedroom outlets, which are finicky, and can false-trip off for reasons no one knows. These are now required by code in most places. My Intellipap can switch to battery operation automatically, and I have a big gel cell I am going to devote to the purpose. A good UPS will not only keep the machine running in a power outage, it will also act as a surge suppressor. (The aforementioned grounding rules still apply.)

Good luck!

[BlackSpinner]

Lightening can damage using the grounding! I had one client where all electronics were fried because the lightening hit the ground beside the building and traveled up the grounding wiring.
When there is lightening disconnect everything - surge protectors are tissue paper to lightening!

[fuzzy96]

are you renting? i ask because in most states rental units must be up to HUD specs. and i am all but certain that non-grounded outlets are a big no-no. a nicely phrased statement to the landlord should get you one installed.

depending on the surge protection device in use an undrounded outlet will give you no protection. some use the ground to discharge the excess electicity. others "clamp" the incoming line to only allow the normal 110 v through.

also not sure what machine you use .
m series with thier power"brick" uses an isolation transformer so there is no connection directly to the unit from the outlet. this is a 10:1 step down unit. thus a surge of 40 volts excess 120v+40v=160v divided by the 10:1 ratio =16v. my power here fluctuates wildly and i've seen 158v . no problems with my cpap. while it will shorten it's life to get surges these things are pretty tough.

if you are going to get big spikes ,big enough to hurt it, there's not much you can do. to get a good surge protector that will do the job you'll pay as much for it as you will a standard cpap. note i said standard. not asv etc.

another thing to remember is if there is a thunder storm in the area and your cpap goes kablooee homeowners and rental insurance should cover it.(check your policy)

[westom]

Now I'm moving someplace with only 2 prong ungrounded outlets. ... Would I get some additional protection by plugging the surge protector into a 2 prong (ungrounded) adaptor? If I do without the surge protector how much risk is there to the cpap or to me?

Receptacle ground is for human safety. Either an appliance connect to the breaker box ground bus via a safety ground wire, OR acceptable protection is obtained by using a GFCI.

That is safety ground. For surge protection, a protector must connect short (low impedance) to earth ground. Wall receptacle safety ground has low resistance but excessively high impedance. If breaker box earthing is upgraded to meet and exceed post 1990 code and if one 'whole house' protector is earthed, then everything inside a house is surge protected - including anything on two wire receptacles.

Even though all grounds are interconnected, how 'connected' determines which ground functions exist. Wall receptacle ground is a safety ground. Too far from earth (high impedance) to act as an earth ground. A protector is only as effective as its earth ground which is why ground from breaker box to earth must be short ('less than 10 feet'), no sharp bends, no splices, separated from other wires, not inside metallic conduit, and every incoming utility wire inside every cable is earthed to the same earthing electrode. Earthed either by direct connection (ie cable TV, satellite dish) or earthed via a protector (ie AC electric, telephone). Proper earthing at the service entrance provides surge protection. Protector and protection are different items.

One 'whole house' protector sells in Lowes for less than $50.

[Gerald]

Midnight.....

If you're serious about surge protection, I know of only one company that I can trust in that field.

Contact Zerosurge.com

Call them and ask for advice. I have their equipment at home and at my office. We had an almost direct hit......it left some outlets smoking......but my Unix server survived....as did all but one of my terminals. Had we not been protected by Zerosurge equipment, I would have lost it all......and my business would have been down for weeks.

Gerald

[feeling_better]

The ground of the 3 prong is usually for human safety. But your cpap equipment most likely has no exposed metal parts at all if it is like M-series. All is encased in plastic. So the chance of you getting any shock from it is practically zero in normal use (that is in a bed room, and not near a sink or wet areas or the machines getting wet.)

On top of that, there is an isolating power supply, (aka the brick), which further isolates the machine from power lines.

And of course, when you are sleeping with cpap, there is no metal connection whatsoever with the machine, the cpap hose is plastic. So from the electrical shock point of view there is nothing to worry about in using it with from a 2 prong outlet.

My own opinion about surge protectors ( I am an Electrical Engineer), is that it is way over rated in its benefits. Most all electrical supplies in developed countries do not have any surges to speak of. If you are in a region with lightnings, or in 3rd world countries, and your power lines coming to the house is overhead (for us even the street power lines are underground), there is a possibility of lightning induced surges present on the power lines. A good surge protector might reduce such surges. But most surge protectors sold to consumers are toys, in my opinion. A good surge protector may be partly effective even without the ground of the 3 prong supply, but that depends on the design.

[westom]

If you are in a region with lightnings, or in 3rd world countries, and your power lines coming to the house is overhead (for us even the street power lines are underground), there is a possibility of lightning induced surges present on the power lines. ... A good surge protector may be partly effective even without the ground of the 3 prong supply, but that depends on the design.

Typically destructive surge occurs maybe once every seven years. So that protection inside every appliance is not overwhelmed, that rare surge must be earthed before entering a building. To make wire impedance low, a ground wire must be short (ie 'less than 10 feet'), no sharp bends, no splices, not bundled with other wires, not inside metallic conduit, etc. Wall receptacle safety ground clearly violates almost every earthing requirement; impedance too high for earth ground. Plug-in protectors are not earthed, avoid all discussion about earthing, and do not even claim to provide protection. A three wire power strip is also a human safety violation on two wire circuits.

A 50 foot romex wire from breaker to receptacle may be less than 0.2 ohms resistance and 120 ohms impedance. When earthing a trivial 100 amp surge, that voltage can be something less than 12,000 volts. How does 12,000 volts find earth ground? Destructively through CPAP or other appliance.

Meanwhile, one 'whole house' protector, at about $1 per protected appliance, will earth 50,000 amps and remain functional. Not a problem when connected low impedance (short, no sharp wire bends, etc.) to earth.

If not obvious, I am also an electrical engineer with a few decades of experience here. Critical to any surge protection is a low impedance (not low resistance) connection to earth. One 'whole house' protector is a solution that costs tens or 100 times less money, does provide protection for other essential appliances such as the dishwasher and furnace, and protects even appliances on two wire circuits receptacles including the CPAP. A better solution that also costs less money.

[2flamingos]

I live in an older home that does not have many grounded outlets (only ones I had installed when I remodeled kitchen 8-10 years ago). I use a standard two-prong outlet, especially since my machine has a standard two-prong plug. While major surges (lightening) can get to any applicane, I am pretty sure that the "brick" that folks complain about on the M-series will stop "minor" surges from getting to the machine. May have to replace the "brick", but that ouwld be better than having to buy a whole ne machine.

We have thunderstorms requently here in Lower Alabama - in fact we are about to get one very soon - it is as dark as dusk at 10 am, and I am not that concerned.

[westom]

I am pretty sure that the "brick" that folks complain about on the M-series will stop "minor" surges from getting to the machine. May have to replace the "brick", but that ouwld be better than having to buy a whole ne machine.

Which works if lightning works like a wave crashing on the beach (surge crashes on your brick). But surges are electricity. That means a path forms from cloud to earth. Then a massive current flows through that path. To damage your brick, a surge must flow from AC mains, destructively through the brick, through the CPAP, to earth ground. That is how destructive surges work.

All appliances have that same 'brick' inside or outside. A 'brick' circuit is why all appliances have protection from most surges. Do you think that 'brick' will stop what three miles of sky could not? Rare surge that does cause damage either goes right through that brick and CPAP, or you earth a surge before it can enter the building. Effective surge protection is not only installed for CPAP. It is installed for everything including clock radios and smoke detectors. That surge is not destructive if earthed by only one 'whole house' protector. A surge that does not enter the building does not harm any appliances.

'Whole house' protection is the only useful solution for two wire receptacles. One sells in Lowes for less than $50. Connected short (no sharp bends, etc) to earth means a surge need not enter your building; need not cause any damage even to a dishwasher or refrigerator. We earth surges so that surges do not blow through that brick - or anything else.