What about thunderstorms?

I don't agree with everything weston is saying, particularly the dollar per appliance price tag for whole house protection (unless you happen to have 400 to 900 appliances, which is the going rate in my area) but see no reason whatsoever to label him (or her) a troll. This poster seems genuinely interested in educating and debunking, wasn't the one who introduced the topic, and shows no sign of arguing for the sake of arguing, attracting attention, or upsetting anyone. Let's reserve the troll label for those who earn it.

I am an electrical engineer and amateur radio operator. I have experience with equipment that's been damaged by lightning. I have attended presentations from the guys who install commercial radio stations and design the lightning protection systems. I know lots of people who've had equipment damaged by lighting strikes.

Sorry, but electricity and lightning don't work the way a lot of you seem to think it does. Don't worry, lightning doesn't work the way a lot of electrical engineers, electricians, surge suppressor salesmen, and scientists think it does either.

1) The electrical wiring, appliances, telephone system, your CPAP system, your body, the earth around your house, and the power company etc. form an electrical network. The components are connected together in various ways. There are various impedances between the various components in the network.

2) When lighting strikes an electrical network, the voltage and current flow to every part of the network. You may have 99% of the current flowing through one path to ground, but some part of it will go to most other parts of the network.

3) Lighting is not a DC phenomenon. Because of the rapid change in voltage and current, it does not flow the way you might think it does. Even a thick copper wire that has a low impedance to a DC current looks like an inductor to an AC current. To the transient (spike) lighting currents, it is not necessarily the one and only path to ground. Some of the current will flow through other paths in the network. At the frequencies involved, nothing in the network is a zero resistance wire, everything is an inductor with a complex impedance involved. Even "ground" is not "ground," but rather a network of impedances. Two pieces of equipment connected to different ground systems can see a big spike.

4) The current in a lightning strike is enormous, and it has a very rapid rate of change. This creates a rapidly changing magnetic field. This causes everything conductive in the vicinity to experience an electric field just like an electrical transformer. A nearby lightning strike can cause inductive currents in nearby circuits that aren't even electrically connected to the house wiring system. Electrical devices that aren't even plugged in can be damaged. Many devices have a transformer in them somewhere. This transformer will pick up the magnetic pulse from a nearby lighting strike.

5) Because lighting induced voltages (including inductively induced voltages) are so high, electrical arcing through the air can occur. Arcing is hard to predict, so lightning surges may go to places where you don't expect it.

6) Lighting strikes vary. The lighting might strike your house electrical service entry point directly, it might strike the ground 10 yards away, or it might strike the power pole half a mile away. It might be a big lighting bolt or a small one. Each one does different things to your electrical network.

OK, so what do you do about it?

1) Surge suppressors aren't foolproof. However, they do improve your odds. If you have a 1 in 50 chance of losing your equipment every year without the surge suppressor, you might have a 1 in 200 chance with a surge protector.

2) The better your surge protection, the better off you are. However, more expensive is not necessarily better.

3) A whole house surge suppressor is not a panacea. Even if it does exactly what it's supposed to do, due to the impedances involved, 0 volts at the whole house surge suppressor is not necessarily 0 volts at your CPAP machine. No surge suppressor is 100% effective, even if it doesn't burn out in the lighting strike.

4) Most surge suppressors will lose their effectiveness over time. Pay attention to the little indicator light that shows it's working and replace it when the light goes out.

5) If you do have a whole house protector or a surge protector strip of some kind, it usually doesn't hurt to have a protector of some kind for the individual device. I use a spike cube brand protector that's about the size of a big electrical plug on each important/expensive/delicate device I have, including the CPAP machine.

6) Unplugging the device isn't 100% protection, but it's pretty darn good. If possible, unplug the cord from the back of your CPAP machine instead of just pulling the plug out of the wall.

7) Even using a battery isn't 100% protection, but it's pretty good, too. Be sure to unplug the battery charger from the battery.

8) Lighting is especially dangerous to things that are connected to two different systems, such as phone and electrical power. If you have a CPAP machine or computer with a phone or wired internet connection, disconnecting the machine from all but one of the systems during a storm helps. TV's often get it because they're connected to both the electrical power and the antenna, cable, DVR, etc.

I'm mostly talking about risk to the CPAP machine, not the user. Surge protection systems are intended to protect the devices, not to protect the user from electrical shock. In some cases, they may actually increase the risk to the human because they conduct the surge into the ground system, and the user may be in contact with the ground system, for instance on the case of an appliance with a grounded plug.

I'm not particularly worried about lighting electrocution from my CPAP machine, but it's just barely possible. I wouldn't sit touching the case of the machine during a lighting storm, though. A heated hose would worry me a bit during a lighting storm because it's got wiring inside, but otherwise, the hose should provide pretty good insulation. Since it's moist on the inside, there's some small chance of current flow even on an unheated CPAP hose. The risks are probably pretty small in any of these cases.

There would be some small risk if you use a pulse oximeter attachment along with the CPAP during a lighting storm. A battery powered oximeter would be OK as long as it's not connected to the CPAP machine or computer.

Headphones connected to the stereo or MP3 player connected to the charger would increase your risk, too.

Holding the computer keyboard, laptop, wired phone, electric blanket, or other wired electrical device while CPAPing would also increase the risk slightly, but I wouldn't be that worried.

There's always some risk for lighting. A lighting bolt could ignore the house, the wiring, the earth ground, trees, etc. and come through the window and strike you in your bed. The odds are a heck of a lot larger that it will strike something else first.

westom wrote:The bottom line fact: nothing will stop a surge.

Not quite true, but even if it is true, you can encourage most or all of the surge to take another path to ground instead of destroying your CPAP machine.

If "nothing can stop a surge," even unplugging the power cord wouldn't protect you, the lightning would jump the 3 foot gap from the electrical outlet to the plug and find the path to the CPAP machine.

westom wrote:
> Lightning cannot be prevented; it can only be intercepted or diverted to a path which will, if well designed
> and constructed, not result in damage. Even this means is not positive, providing only 99.5-99.9%
> protection. …
> Still, a 99.5% protection level will reduce the incidence of direct strokes from one stroke per 30 years ... to
> one stroke per 6000 years ...

So yes. A ‘whole house’ protector at only $1 per protected appliance (a wallet friendly price) only does 99.5% protection. Somehow a strip protector does a whopping 0.2% while costing $20 or $150 per protected appliance? Very wallet unfriendly. So why do you recommend it? $1 for 99.7% protection. $25 or $150 for 0.2% protection. Why would anyone recommend a power strip protector? Because subjective legends invented by advertising are somehow honest?

westom,

Our three-story house is standing tall high on a hill where lots of violent thunderstorms blow through. I want to have installed a whole house protector the next time I have an electrician out. This is for concern of all electrical equipment in the house, not particularly my CPAP.

Can you provide links to some recommended equipment?

Thanks,

archangle wrote: If "nothing can stop a surge," even unplugging the power cord wouldn't protect you, the lightning would jump the 3 foot gap from the electrical outlet to the plug and find the path to the CPAP machine.

Unplugging is how to divert a surge destructively through some other appliance. Once inside, that energy will hunt for and find earth ground. Appliances are victims. No protection stops a surge.

An example. Does a town dike stop a flood? Of course not. Only thing that stops flooding is a big path downstream. A dike can help divert that flood downstream. But without a downstream path, nothing stops the flood.

Without proper earthing (connected to earth directly or via a ‘whole house’ protector), then superior protection inside all appliances is overwhelmed. Nothing can stop that surge. Any plug-in protector that acts like a dam is literally blown over by the flood. The downstream path - a 'whole house' protector - must exist to have effective protection.

Early 20th Century Ham radio operators learned this. They would disconnect the antenna lead. Even put it inside a mason jar. And still suffer surge damage. Damage stopped only when they earthed the antenna wire.

Best protector that costs about $1 per appliance is a 'whole house' protector. If properly earthed, it only does maybe 99.7% of the protection. As noted repeatedly, one sells in Lowes and Home Depot under the Cutler-Hammer brand name for less than $50. Other also responsible companies (ie Siemens) also provide them so that direct lightning strikes do not even harm that protector. Or a CPAP. A 'whole house' protector is essential to also protect power strip protectors.

A protector is only as effective as what absorbs all that energy – earth ground. Protection is always about where that energy dissipates.

Roster,

You might check with your electric company for a whole house surge protector. The local electric company here offers a whole house unit that they install and rent by the month. Mine is about $5.00 per month. It attaches to the meter base so no fitting is necessary. I have had one for several years and haven't lost any appliances since it was installed. I still use individual surge protectors on the sensitive appliances.

I also have a charged 12 volt battery that I use when the thunderstorms approach. We tend to get them frequently here in eastern Oklahoma.

Jeeper

Archangle has provided an excellent overview of the lightning strike issue.

However it looks like Westom is still struggling with the concept of fuses.

westom wrote:
5 amps through a 32 volt fuse create same watts that melt a 250 volt fuse. Only current blows a fuse - not voltage. Same 5 amps and near zero voltage also trips a 32 volt, 250 volt, or 10,000 volt circuit breaker. Voltage is irrelevant when the fuse blows. That fuse has no idea which voltage is driving 5 amps ... until after the fuse blows or circuit breaker trips.

Voltage number only defines if a fuse can interrupt electricity. If its voltage number is too low, a blown fuse continues conducting current. 5 amps from a 12 volt source will trip a 10,000 volt breaker just like 5 amps from a 1000 volt source will. Fuses and circuit breakers don't know what the voltage is. Only know what the current is.

5 amps at 32 volts is 160 watts. That means that a 5 amp 32 volt fuse blows at around 160 watts. A 5 amp 250 volt fuse has no problems with a load of 160 watts and it will handle that without problems. With the 250 volt 5 amp fuse you need to increase the load to 1250 watts before it thinks about blowing.

Going a step further, if you look at a 32 volt 5 amp fuse and compare the fuse link with a 250 volt 5 amp fuse you will see that the higher wattage fuse link will be larger. A larger wire can handle higher wattage without heating up.

While the current for each case is the same (5 amps) the wattage is different (160 watts versus 1250 watts). As you can see, the wattage to blow a 32 volt 5 amp fuse is different than the wattage needed to blow a 250 volt 5 amp fuse.

When a fuse blows, the current stops. You have an open circuit under normal, and above normal operating voltages. As I detailed earlier, an inch gap in air has a dielectric value of around 8000 volts. If you blow your fuse and the lightning surge has dropped to below 8000 volts, nothing will flow through your blown fuse. If you put a 32 volt fuse in a 250 volt application and it blows, the 250 volt application will stop working because of the open circuit.

Now, if you take a direct lightning hit the fuse protection will not be enough to protect you.

The main "issue" with fuses is that they do not protect against transients. A surge can pass through, and if the fuse wire doesn't heat up and melt, it is just passed on to your electrical components.

OK, back to Archangle and his information on protecting a ham radio set up...

roster wrote: Our three-story house is standing tall high on a hill where lots of violent thunderstorms blow through. I want to have installed a whole house protector the next time I have an electrician out. This is for concern of all electrical equipment in the house, not particularly my CPAP.

Effective 'whole house' protectors were listed in a first post:
How do you protect your machine from electrical spikes?

Names include ABB, General Electric, Square D, Intermatic, Leviton, Keison, and Siemens. A Cutler-Hammer solution sells in Lowes and Home Depot for less than $50. If your CPAP needs protection, then so does the furnace, air conditioner, dishwasher, and ... what most needs protection during a surge? Smoke detectors.

Important numbers. Protector must protect from all types of surges including lightning. Lightning typically is 20,000 amps. So a minimal 'whole house' protector starts at 50,000 amps. That is simple science.

The art is how that protector connects to earth. View your breaker box. A bare copper quarter inch wire may connect that box to earth by going up over the foundation and down to earth. OK by code. And woefully insufficient for surge protection. Bundled with too many wires. Sharp bends over the foundation. Too long. For surge protection, that same wire must go through the foundation and down to an earthing electrode. Short, no sharp bends, and separated from other wires.

How to increase the quality of that protector? Increase earthing. A protector is only as effective as its earthing. Multiple ground rods or even a buried ground loop increases protection. Water pipes are insufficent. Even lead solder joints compromise protection. That earthing must both meet and exceed post 1990 code.

Every incoming wire (overhead and underground) must connect short as possible to that earth ground. Worry less about the protector - simple science. Worry most about what defined protection - the earthing. Even applies if a protctor is installed by a utility. They don't install /upgrade earthing. You must.

Defined is a protector. 50,000 amps defines protector life expectancy over 'many' surges. Defined is protection. Protection during 'each' surge is defined by quality of and connection to single point earth ground.

Some would also consider lightning rods. However, direct lighting strikes (ie to AC wires down the street) more often strike appliances rather than roofs.

One final point. Above is your 'secondary' protection system. Every protection layer is defined only by the one critical component - earth ground. Also inspect your 'primary' protection system. A picture of what to inspect:
http://www.tvtower.com/fpl.html

HoseCrusher wrote: When a fuse blows, the current stops. You have an open circuit under normal, and above normal operating voltages. As I detailed earlier, an inch gap in air has a dielectric value of around 8000 volts. If you blow your fuse and the lightning surge has dropped to below 8000 volts, nothing will flow through your blown fuse.

And again. When the fuse blows, it creates plasma. Fuse designs are limited by how fast that plasma converts to gas. Some fuses are cheap and simple. Are only designed to stop 32 volts after the fuse blows. Others with the same size gap are designed to only stop 250 volts. Some fuses with the same current rating are designed to stop 10,000 volts. That voltage does not define when a fuse blows. Only current defines when a fuse blows. Again, I am mystified why such a simple concept has you so confused.

Does not matter what the gap is after plasma is gone. What matters is how much voltage a fuse can block after it has blown. No 250 volt fuse will stop a surge. First, that surge is long gone and done before the fuse can blow. Second, surge voltages will increase as necessary to blow through a fuse. Only fact that is relevant here: No fuse or circuit breaker can stop a surge. None. Surges increase voltage as necessary so that a same current will flow. Anyone promoting fuses for surge protection has too much to learn.

Meanwhile, the only effective protection for a CPAP means earthing a 'whole house' protector. Anything a power strip protector might do is already done better inside the CPAP.

westom wrote:Unplugging is how to divert a surge destructively through some other appliance. Once inside, that energy will hunt for and find earth ground. Appliances are victims. No protection stops a surge.

An example. Does a town dike stop a flood? Of course not. Only thing that stops flooding is a big path downstream. A dike can help divert that flood downstream. But without a downstream path, nothing stops the flood.

Without proper earthing (connected to earth directly or via a ‘whole house’ protector), then superior protection inside all appliances is overwhelmed. Nothing can stop that surge. Any plug-in protector that acts like a dam is literally blown over by the flood. The downstream path - a 'whole house' protector - must exist to have effective protection.

Early 20th Century Ham radio operators learned this. They would disconnect the antenna lead. Even put it inside a mason jar. And still suffer surge damage. Damage stopped only when they earthed the antenna wire.

Best protector that costs about $1 per appliance is a 'whole house' protector. If properly earthed, it only does maybe 99.7% of the protection. As noted repeatedly, one sells in Lowes and Home Depot under the Cutler-Hammer brand name for less than $50. Other also responsible companies (ie Siemens) also provide them so that direct lightning strikes do not even harm that protector. Or a CPAP. A 'whole house' protector is essential to also protect power strip protectors.

A protector is only as effective as what absorbs all that energy – earth ground. Protection is always about where that energy dissipates.

1) A lightning strike is not measured in gallons like a flood. The idea that lightning strike destructiveness is equivalent to a flood is wrong.

A perfect lightning suppression system would be a zero resistance/impedance system going to ground. The voltage would be zero, so the power and energy in the suppression system would be zero as well. The energy dissipation would be in the plasma arc between the cloud and whatever it struck. Power = volts times current. No volts across your house, no power.

2) The destructiveness of a power surge has nothing to do with the voltage between your device and the earth. It's the voltage spike between the hot, neutral, and earth connections in the plug your device is plugged into that your device "sees". A surge suppressor located at the device will give you better protection than one located away from the device because a lighting strike will induce voltages in the hot, neutral, and earth wiring in your house. Part of the protection a surge provides is because it may actually raise the voltage on the earth and neutral wire at the plug to match the spike on the hot wire. This actually applies even to a whole-house surge protector because the ground wire and the soil around your house are not perfect conductors, especially to AC or transient voltages.

3) Grounding an antenna increases your chance of getting a lighting strike. The better solution is to unplug the antenna outside and throw the end of cable away from your house.

4) A whole house surge protector IS probably a good idea. Just be sure you check it often to see that it's still protecting and plan on replacing as needed. Even a whole house surge protector may stop protecting and need to be replaced after a while.

5) Even if we are talking water, dams do stop floods as long as the available water retention capacity of the reservoir exceeds the volume of water coming down the stream. That doesn't really mean that much in terms of lightning protection for CPAP machines, though.

westom wrote:Anything a power strip protector might do is already done better inside the CPAP.

No. The surge suppressor will often give its life to protect the circuitry inside your CPA machine. The little "protected" light on the surge suppressor will go dark and I can replace it.

My CPAP machine doesn't have an "internal surge suppression circuitry working" light and doesn't have an easy or inexpensive way for me to replace the internal surge suppressor circuit if it does go bad and I somehow figure out that it has gone bad.

I'll be really glad if my surge suppressor on the power cord for the CPAP dies protecting my CPAP machine and keeps any damage to be done to my CPAP machine's internal surge suppression.

Yes, internal surge protection in the CPAP machine is a good thing. Adding an external protector is still a good idea.

By the way, has anyone gotten a whole house surge protector installed by an electrician? What did it cost? Does it have easily viewed "protector working" lights and do you check them often? How many years service have you gotten between replacements? As I say, a whole house protector is a good idea, but it's NOT "set and forget."

archangle wrote: [No. The surge suppressor will often give its life to protect the circuitry inside your CPA machine. The little "protected" light on the surge suppressor will go dark and I can replace it.

OK. Now I understand your confusion. You have not designed surge protection systems.

MOVs must not fail catastrophically as each manufacture datasheet says. Otherwise scary pictures result. A grossly undersized protector must disconnect as fast as possible so that the Absolute Maximum Parameters are not exceeded.

A light that indicates protector failure says, "This protector was too grossly undersized for that one surge. So protector parts have been completely disconnected to avoid scary pictures and house fires."

No effective protector fails that way. But when selling near zero protection for obscene profit margins, then grossly undersizing a protector promotes sales. You have done just that. Promoted a protector because it was so grossly undersized. Undersized protectors fail on surges too tiny to harm a CPAP or any other appliance. That gets the most naive to recommend it. Meanwhile, protection already inside the CPAP and other appliances made that surge irrelevant.

Protectors fail by *degrading*. Again, please read data sheets. Degrading means its threshold volts changes by 10%. How does that light report a 10% degradation? It doesn’t. That light cannot report an acceptable failure mode. That light only reports when a protector was grossly undersized.

Any protector that sacrificed itself is the classic scam. It disconnected as fast as possible so as to not create scary pictures. But house fires may result when it does not disconnect fast enough – as the NC fire marshal explains.

Norma demonstrated how crappy power strip protectors can be in "The Power Outage" on 27 Dec 2008:
> Today, the cable company came to replace a wire. Well the cable man pulled a wire
> and somehow yanked loose their "ground" wire. The granddaughter on the computer
> yelled and ran because sparks and smoke were coming from the power surge strip.

It does not happen often. But ineffective protectors that somehow sacrifice themselves to save the appliance do what Norma saw. Or did that grossly undersized protector somehow make hundred of thousands of joules just magically disappear? So tell me. How did that power strips with no earth ground magically make hundreds of hundreds of thousands of joules disappear? Sacrificed itself. How? Where are your numbers that show protection from destructive surges? Why is that protector only hundreds of joules? So that it can fail ASAP. And then urban myths claim it sacrificed itself.

And protector that sacrifices itself is so profitable that even Monster is selling them.

Roster asked for effective protection. Provided was the minimally sufficient number – 50,000 amps. Number provided because a protector must not sacrifice itself. In high lightning areas, some install 100,000 amp protectors because that light must never indicate failure. In your case, a surge too tiny to harm nearby appliances easily destroyed a grossly undersized power strip protector. Fortunately, no scary pictures results – this time.

Best and complete protection for a CPAP is also the only solution found in facilities that cannot have damage. Properly earthed ‘whole house’ protector. A protector is only as effective as its earth ground – which sacrificial protectors do not have and will not discuss. They actually got you to believe is its 1000 joules sacrificed itself to make hundreds of thousands of joules just disappear? Please. Learn from datasheets. A protector that fails promotes profits; not protection. The effective protectors – every time – have the short wire to earth ground. So that hundreds of thousands of joules do not even harm the protector.

archangle wrote: 1) A lightning strike is not measured in gallons like a flood. The idea that lightning strike destructiveness is equivalent to a flood is wrong.
A perfect lightning suppression system would be a zero resistance/impedance system going to ground. The voltage would be zero, so the power and energy in the suppression system would be zero as well…
2) The destructiveness of a power surge has nothing to do with the voltage between your device and the earth. It's the voltage spike between the hot, neutral, and earth connections in the plug your device is plugged into that your device "sees".

You are again saying you have some electrical knowledge. And yet have no idea how surges work. Why things are damaged. Quite obviously from your numbers, you never designed this stuff.

The river perfectly demonstrates how surges protection works. Surges are not voltages as you keep assuming. Surges are a current source. That means voltage increases as necessary so that current will flow – unobstructed even through a CPAP. If a surge is 5000 amps, voltage will increase as necessary so that 5000 amps flow. Nothing stops a surge. Nothing. Especially not a power strip protector. If a river does not have a downstream path, river height increases (just like voltage) so that the same gallons per minute still flow. If you do not understand these similarities, then you do not understand basic surge protection. And never learned why one ‘whole house’ protector is the best and only protection needed by a CPAP.

A perfect suppression system would be zero impedance to earth ground. Correct. And that is impossible. So we make wires shorter - not thicker – shorter to lower impedance. Wire length (as short as possible) is critical to surge protection as explained to roster. But again, you did not do this stuff. So you don't yet understand what is important. Why does every effective protector always have a separate and dedicated earth ground wire? Because a connection to earth must be so short. Otherwise the protector promotes itself by being grossly undersized. Ie that failure light.

Grounding an antenna does not increase chance of lightning strikes. Please learn from hams who do this stuff. Find various discussions by Bill Otten. He has probably done it all. Or the various discussions in rec.radio.amateur.antenna where your myth is routinely trounced. Or learn from the case study of a Nebraska radio station:
> Based on a belief that "too much" grounding was attracting lightning strikes, grounding
> connections on the tower's six sets of guy wires had been disconnected sometime in the
> past (Figure 4). This action may, in fact, have helped direct lightning discharge current
> down the antenna tower itself, bringing the strike closer to the studio/transmitter
> building.

You do not even know how MOVs work. How protectors are designed. You promoted the very popular lie about sacrificial protectors. And now claim that earthing can increase your chance of getting a lighting strike. Please sir. You are not doing what any responsible engineer I work with would ever do. You automatically believe hearsay. Explains why you do not understand surge protection and use grossly undersized power strip protectors.

A nearby lightning strike can cause inductive currents in nearby circuits that aren't even electrically connected to the house wiring system.

A lightning strike near a long wire antenna can create thousands of volts on that antenna. Then we earth it with an NE-2 neon glow lamp. A milliamp through that lamp reduces thousands of volts to tens of volts. Because induced energy of nearby lighting is near zero. That induce surge is promoted only when numbers are ignored.

A direct strike to a lightning rod meant tens of thousands of amps – the entire lightning bolt – flowing to earth on a wire. Four feet away from that wire was an IBM PC. The entire lightning current, according to you, must have vaporized the PC. Reality. The direct lightning strike only four feet from a PC that did not even blink. Please learn the numbers and technology before assuming so many myths. Nearby strikes (induced surges) do not cause damage. Direct strikes are why we earth surge protectors.

It's the voltage spike between the hot, neutral, and earth connections in the plug your device is plugged into that your device "sees".

Again you are confusing surges (massive currents) with voltages. A voltage spike between hot, neutral, etc is not destructive. Made irrelevant by protection already inside every appliance. Is even defined by numbers in international design standards.

A destructive surge is a current approaching on any or all of those wires. Destructive surges enter on all AC wires. And exist via some other wire, human body, or other conductive material such as wood or concrete. Once that energy is inside a building, it will find a destructive path to earth. Either a surge remains outside the building. Or no effective protection is possible. Only way to stop that current is to not stop it. To connect (divert, shunt, bond, switch) to earth before it enters a building. And that is done in every building that can never have damage - a 'whole house' protector.

Demonstrated in a 1994 IEEE paper by Martzloff, a protector too close to appliances can simply put that surge on all three wires. Gives a surge even more paths to find earth destructively via appliance. But again, I am citing professionals who did the research. Not making subjective claims from popular myths. Which is why a ’whole house’ protector is the best and only protection needed by a CPAP.

Meanwhile, the best and only protection needed for the CPAP (and everything else in the house) is one properly earthed ‘whole house’ protector.