Does an all-electric house need surge protection?

Electrical power surges are a hazard that you might be familiar with, or even been a victim of. A power surge is a brief spike of voltage that can damage any electrical appliance, but are a particular problem for sensitive electronics.

Many consumers are familiar with surge protectors, which is a feature often included in power strips. There’s a good chance that you have at least one surge protector in your house to protect electronics such as a television, computer, internet router, or audio system. Surge protectors work by limiting the voltage on an electrical circuit to a safer level.

However, major appliances, like heat pumps, stoves, and clothes washers are often overlooked. These appliances contain sensitive electronics and can also be vulnerable to power surges. If you have an all-electric home, they’re the only type of appliance you have, which means that you may have tens of thousands of dollars worth of equipment that are vulnerable.

But you can’t plug a heat pump into a power strip, so how does a homeowner protect their equipment?

Fortunately, there are relatively simple solutions that protect an entire home against surges. They are installed at your electrical panel and can be used for new installations or retrofitted into an existing panel, even if the panel is full.

Even if you decide that the cost of installing surge protection isn’t worth it, understanding what power surges are and how to protect against them is a good idea.

What are electrical power surges?

A power surge or spike is a brief increase in voltage or current on an electrical circuit. They can be caused by a wide variety of events: lightning strikes, falling tree branches, substation faults or other equipment failures, and power restoration after a blackout. Apparently, squirrels chewing on electrical equipment is a common problem. One time, an osprey caused a blackout for 2,100 utility customers in New Jersey by dropping a fish onto a transformer ¹.

Smaller power spikes, also known as power line noise, can originate within a home from equipment such as motors (like the compressor in your refrigerator) and hair dryers.

The normal voltage in home electrical circuits is 120v or 240v, but power surges are typically measured in kilovolts (kV). One kilovolt is 1,000 volts, so a circuit experiencing a power surge can be thousands of volts higher than normal. Power surges are brief and measured in tens of microseconds, but because the voltage is several times higher than appliances are designed for, even a spike lasting just a few milliseconds can cause serious damage.

While lightning strikes are the most dramatic source of power surges, mundane causes like faulty utility equipment are much more common.

Lightning and power grid failures are external sources of power surges, but they can also be caused by equipment internal to your house. If you’ve ever noticed your lights flicker when a hair dryer is switched on or off, you’ve experienced an internal power fluctuation. Power tools, refrigerators, and air conditioners are some common sources. One thing to keep in mind is that these aren’t always spikes, but temporary drops in voltage. Surge protectors won’t protect against voltage drops – what you would need instead is a power conditioner.

While the power surge from a table saw isn’t the same intensity as one caused by a lightning strike, repeated exposure to low level power spikes can eventually damage electrical equipment. Some electronics have built-in surge protection devices called metal oxide varistors (MOV). While MOVs can protect electronics from small spikes, they degrade when used and can eventually fail.

This is one reason why surge protection devices are a good idea for homeowners.

Are all-electric homes more vulnerable to power surges?

It might seem counterintuitive, but homes that only have electrical appliances aren’t necessarily more vulnerable to power surges than homes that have a mix of appliances powered by electrical, gas, or other fuels.

This is because electronics, which are found in even simple appliances like toasters and water kettles, are the most vulnerable component in modern appliances. Unless your alternative is a vintage gas range that doesn’t have any electronics, an induction stove isn’t really more likely to be harmed by a power surge than a gas model.

The same is true if you’re comparing a gas furnace to a heat pump. A forced air gas furnace has an electric blower motor and is controlled by an electronic control board. While a heat pump does have additional electrical components such as compressors and relays, it’s the sensitive computer circuitry that is most likely to fail due to a power surge. This means that you’re not really at any greater risk by choosing electrical heating over gas or oil.

In an example of this, This Old House has a short video segment ² from a homeowner who experienced a power surge that damaged her microwave, kitchen lights, house alarm, and even refrigerator ice maker.

Electrical appliances might be more expensive

While switching your gas appliances to electric might not make you more prone to power surges, one consideration is that electrical appliances are sometimes more expensive than gas appliances. As an example, you can expect an induction range to start around $1,000. However, you can find entry level gas or conventional electric ranges for about half that price. Induction ranges are a newer technology and tend to be aimed at the higher end of the market – you can’t get a $500 induction range yet.

Because of this, surge protection for an all-electric home might be an important consideration not because the appliances are more vulnerable to surges, but because the replacement cost is higher.

What is a surge protection device?

A surge protector, which is commonly referred to in the electrical industry as a surge protection device (SPD), limits the amount of voltage on a electrical circuit to a safer level. When the voltage on a circuit exceeds a safe level, the SPD will send the excess electricity to the ground or neutral line of the circuit.

There are different types of surge protectors, as well as specifications that are useful to understand. This article will mostly focus on SPDs that can protect an entire house, but I’ll briefly mention the other types as well.

Type 1 and Type 2 surge protectors are whole-house surge protectors that are installed at your electrical panel. Type 1 SPDs are often installed on the “line side” of the electrical service, which means that they are installed between the utility transformer and your electrical panel. Type 1 protectors can also be installed on the “load side” of the panel, which means they are connected in the panel downstream of the main breaker. Type 2 SPDs are usually installed on the load side.

Both Type 1 and Type 2 SPDs will protect your home against power surges from external sources, but Type 1 devices can generally handle higher electrical current – even lightning strikes that directly strike utility infrastructure.

Type 2 SPDs can protect against surges from indirect lightning strikes ³, as well as surges generated by sources inside your home.

Here’s an example of an SPD installed at an electrical panel:

Type 3 surge protectors are point-of-use devices that protect the equipment they’re plugged into. They’re the power strips that you may already be familiar with, but they’re also available as power outlet replacements if space is a concern.

Even if you have a Type 1 or Type 2 surge protector installed, you may still want to have Type 3 protection for valuable electronics: maybe you just bought a 70-inch OLED tv or audiophile-quality stereo system for your media room. Type 3 SPDs can “clamp down” to a lower voltage than Type 1 and 2 devices. Also, higher quality Type 3 surge protectors often come with a warranty against damage to connected devices.

There are also Type 4 and 5 SPDs that are embedded directly into devices and act as a last line of defense. Your devices will last longer if you protect them by adding surge protection “upstream” – that is, by using Type 1, 2, or 3 surge protectors on your electrical circuits.

Understanding surge protector specifications

There are a few key specifications to look for when you’re shopping for surge protection devices.

The first can be referred to as the voltage protection rating (VPR), let-through voltage, or clamp-down voltage. This is the maximum voltage that the suppressor will allow to pass through to the connected circuit. Standard UL ratings for VPR are 330v, 400v, 500v, 600v, and higher. You’ll find that Type 1 SPDs will generally have higher VPR ratings than Type 2, and Type 3 SPDs will tend to have lower ratings than Type 2. This is a reason why you might want to take a layered defense approach by using a combination of Type 1, 2, and 3 SPDs in your home.

The second specification to look for is surge current rating ⁴. You can think of this rating as the total surge protection capacity of the SPD. Most SPDs that consumers use are based on Metal Oxide Varistors (MOVs). MOVs have high capacity and excellent reliability, but degrade with each high level surge they handle ⁵. Eventually, with repeated spikes, the MOVs in a surge protector will fail and the device will need to be replaced.

In general, a higher surge current rating means that the device will have better longevity. In Type 1 and Type 2 devices, this rating is often listed as kilo-amperes (kA) while Type 3 surge protection power strips may list a rating in Joules. SPDs will have an LED light to indicate when the device has been depleted and needs to be replaced.

Finally, good SPDs will be multi-mode, which means they can send the excess current down a different pathway depending on where the power surge is occuring. For a 120v SPD, the specifications may indicate that it can work in L-N (line-to-neutral), L-G (line-to-ground), and N-G (neutral-to-ground) mode. Having a multi-mode SPD is often beneficial to protect against internally-generated power surges.

A side note about GFCI and AFCI protection

There are other types of electrical circuit protection that can be confused with surge protection. Arc faults and ground faults are caused by wiring failures and can cause fire or electrocution hazards. If you have a newer power outlet in your kitchen or bathroom, you might notice that it has a little green LED light. This is likely a ground fault circuit interrupter (GFCI), and it will protect you from electrocution if – for example – your toaster or hair dryer has a wiring fault that causes current to leak into the body of the appliance.

GFCI and AFCI protection can be incorporated into power outlets or circuit breakers and, similar to surge protectors, use LED lights to indicate whether they are operating correctly. Despite these superficial similarities, GFCIs and AFCIs do not protect against power surges and should be not confused with one another. You can (and should) have both types of protection on your electrical circuits if you want highest level of safety.

Will a surge protector guarantee that your expensive heat pump or induction range won’t be damaged?

Good surge protection devices will minimize the possibility of damage to your high-end appliances, especially if you select one with a lower voltage protection rating. However, the voltage that leaks through during a spike will still be higher than normal and can cause damage, so the protection they provide isn’t foolproof. As mentioned earlier, high quality SPDs will also include a warranty that covers (up to a limit) any surge-related damage to your connected appliances.

If you have multiple appliances that you want to protect such as a heat pump, induction range, EV charger, and heat pump hot water tank, the best approach would be to add a Type 1 or Type 2 SPD to your electrical service, or even both. If you have both a Type 1 and Type 2 SPD, the Type 1 device will protect against large external surges while the Type 2 device will protect against internal surges, and also further reduce any voltage spikes if it has a lower VPR than the Type 1 device installed upstream.

HVAC companies also make surge protection devices specifically for heat pumps, and some HVAC companies will provide them with their installations. While the option is a good one, an HVAC SPD might not provide any better protection than one that is installed at your electrical panel, nor will it protect other appliances in your home. That said, adding additional layers of protection can be good, so you’ll want to discuss with your contractor which is the most economical and effective approach.

NEC 2020 code means that new and upgraded installations require surge protection

A change to the 2020 version of the National Electrical Code (NEC) means that electrical panels in all dwellings will now need to have Type 1 or Type 2 surge protection installed ⁶. This applies to new installations and any existing installations where the equipment is replaced. (This means that if you need your electrical panel replaced, the new one will need to have an SPD.)

This means that you might already have surge protection in your home. To find out, take a look in and around your electrical panel for a device similar to the one pictured above. It should have status lights and be clearly labelled. If you have one, that’s good news! All your appliances will have a good level of protection, and the only thing to consider is whether you want additional layers of protection on specific appliances.

How to install whole-house surge protection

In case it wasn’t obvious, you’ll want to consult a qualified electrician if you want to add whole-house surge protection to your electrical service. Working within an electrical panel is dangerous and beyond the skill level of most homeowners.

A good electrician will let you know whether a Type 1 or 2 device is best for your situation and can also advise you on an approach if you want a layered defense against power surges. Combining Type 1, 2, and 3 devices in your home will provide you the best possible protection and might be a good idea if you experience frequent power outages or have appliances that are particularly high value. Each successive layer of surge protection will clamp the voltage of surges to a lower, safer level and minimize the possibility of damage. This will also help extend the life of your SPDs. For example, instead of having multiple Type 3 SPDs in your home being destroyed by a major surge, you might be able to limit the damage to a single SPD installed at your electrical panel.

As always, when working with contractors on any sizeable project for your home, be sure to get multiple quotes.

Bottom line: whole-house surge protection is a good idea for any home

Power surges are an unfortunate event to experience, as they can cause widespread damage to the electrical appliances in your home.

If you have an all-electric house, you probably aren’t any more likely to be the victim of a power surge. This is because nearly all appliances these days contain electronics, which are the most sensitive part of a device. A modern gas range will have an electronic interface, just as an induction range does.

What may require special consideration for all-electric homeowners is that the appliances tend to be more expensive. For this reason, even if you aren’t any more likely to have an appliance damaged by an electrical surge, the cost of replacing your equipment may be higher.

Fortunately, it’s relatively low cost to protect all of the electrical appliances in your home. A Type 1 or 2 surge protection device starts at around $100, plus the cost of installation. If you have tens of thousands of electrical appliances in your home, like many people do, that small cost can be well worth it.

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