Does SMT1000 still power outlets when Surge Protection is gone?

[digigurl]

I have a Smart-UPS SMT1000 UPS. It's still working in terms of switching to battery when the power goes out. However, I'm wondering about surge protection. My question is... if the MOVs in my UPS have reached the point that they are not providing any protection at all, does the UPS still continue to power its outlets with AC power or battery? OR... does it detect the MOVs are "spent" and shutoff power to its outlets? I'm not very technical so thanks for replying accordingly. 

[Teken · Accepted solution]

Generally speaking (SPD) Surge Protective Devices are classified in *Type* that span the following:

- Type 1: Service Entrance (Line Side)

- Type 2: Service Panel (Load Side)

- Type 3: Point of Use (Outlet)

- Type 4: Inline with equipment

Given the APC UPS is a Type 3 (Point of Use) the MOV inside typically is rated much lower than Type 1 / 2. MOV's by design short to ground when their voltage threshold has been met. Unlike shoes you can not see or know if they are worn out unless its a complete rupture from a direct lightning strike etc.

MOV's that are degrading will continue to allow the UPS to operate but offer less protection when called upon. A MOV that has opened up will cause the UPS to fail and possibly declare a fault by beeping, LCD message, or just won't turn back on.

As stated up above a SPD System should be installed (Type 1 ~ 4) and present to offer you and the connected equipment the most protection. This is only superseded by having a solid low resistance (< 25 Ohms) Earth Ground present and having everything connected to this single point grounding system. 

[digigurl]

Thanks for your thoughtful explanation and outlining the different levels of surge protection. It's more involved than I realized. 

[Teken]

In a nutshell MOV’s only activate based on their designed and specified voltage. Anything below that voltage threshold the MOV does nothing. Should a MOV or any part of the internal SPD system fail the UPS more than likely would stop operating. It should be noted 80% of all surges are created internally within a home / business. These surges are created by fridge, freezer, sump, well, HVAC, stove, dryer, etc. 

[digigurl]

Perhaps I should mention that I’m interested in protecting a computer and (future) NAS from surges. In two of my previous computers, the power supply was the first thing to die. I suspect it was from surges. One computer was always on the SMT1000, but perhaps little surges reached the PSU. Not losing data and preventing data corruption is also important.

Am I interpreting correctly that only Types 3 and 4 SPDs address internal surges? Is it likely that little internal surges go right through to the devices since these surges don’t meet the MOV threshold?

What kinds of Type 4 SPDs are there and can they be used in conjunction with a UPS? I’m guessing “No” since surge protectors cannot be used with UPSs. 

Since the state of protection remaining with the MOV is uncertain, what is a reasonable action to take if you want Type 3 surge protection? E.g. Replace the UPS? 

If the UPS is still functional as a backup battery, but the MOVs might be worn due to surges over the years, would a person who understands electronics (not me) be able to replace the MOVs? What kinds of things would they need to consider? Thanks.

[Teken · Accepted solution]

---

@digigurl wrote:

Am I interpreting correctly that only Types 3 and 4 SPDs address internal surges?

- Yes, Type 3 / 4 are designed to address surges created within the building. Generally speaking their very design is to absorb and fail at a much lower surge / spike event when compared to a SPD Type 1 / 2.

Is it likely that little internal surges go right through to the devices since these surges don’t meet the MOV threshold?

- You'll need to read up on and know the following metrics: Let through, clamping voltage, Joules. Generally speaking for Type 3 / 4,  330 VAC (Volts Alternating Current) RMS is standard in consumer SPD's as it relates to *Clamping Voltage* anything higher should be avoided. Joules, rating refers to how much energy your surge protector can absorb. In this case, a higher rating equals better protection. A surge protector with a rating or 1,000 joules will last longer than a surge protector with a rating of 500 joules.

Below is a resource link from APC FAQ as it relates to Let Through: https://www.se.com/ca/en/faqs/FAQ000240088/ 

What kinds of Type 4 SPDs are there and can they be used in conjunction with a UPS?

- A Type 4 SPD is normally wired in series before an industrial device, But consumers can install the same on their appliances / devices such as furnace, dishwasher, washer, air conditioner, etc. 

I’m guessing “No” since surge protectors cannot be used with UPSs. 

- APC does not recommend a SPD be connected to the outlets of the UPS. The APC FAQ stated the following: https://www.apc.com/us/en/faqs/FA158852/

It should be noted every large Enterprise, Government, Military, Hospital, Police, Fire, etc. They use and are protected by a Type 1, 2, 3, 4 SPD and a UPS is powered by the same without issue. 👍 🤔

Since the state of protection remaining with the MOV is uncertain, what is a reasonable action to take if you want Type 3 surge protection? E.g. Replace the UPS? 

- You could purchase another UPS with better surge protection

- You can install a Point of Use Type 3 SPD Outlet with better specifications.

If the UPS is still functional as a backup battery, but the MOVs might be worn due to surges over the years, would a person who understands electronics (not me) be able to replace the MOVs? What kinds of things would they need to consider? Thanks.

- Any repair shop could replace the MOV's in the UPS with either the same component or better. The important things which the technician would consider is the operating voltage - that's just a given. More importantly they could install larger MOV's, hybrid MOV's that incorporate thermal protection and a fire proof shroud. As noted up above they could spec a MOV with better let through, joules, and clamping voltage.   

---

Answers Inline: It should be noted MOV's SAD, GDT, by their very nature are designed to sacrifice, degrade, and fail when called upon. There are other technologies that are not sacrificial in nature and thus offer longer service life, better protection, and higher performance.

This Panamax outlet is a Type 3 SPD which has a Protect / Disconnect design. https://panamax.com/product/max-in-wall-15-amp-duplex-with-surge-protection/

You can see this technology in action here: https://www.youtube.com/watch?v=j53qtYc5ZeE 

Another company is called Zero Surge: https://zerosurge.com/ 

There are other companies that use the same patented technology to absorb, reduce, and shunt to ground a surge. They use a combination of transformers, inductors, filters, and capacitors to allow their products to sustain repeated low & high surge / spike events. 

As stated earlier surge protection requires everything in the home to be sound. This starts with a low resistance Earth Ground (<25 Ohms) that is bonded correctly and firmly to the service (meter) entrance. That same Earth ground is connected to the Service Panel inside the home.

As a home owner anyone with common sense can inspect or hire out a licensed electrician to validate all of the wires in the Service Panel are firmly tied down. That the Earth ground is properly *Bonded* to the water pipe. That all wiring connecting the outlets and switches in the home are firm and secure.

The only way to know if your home has a low resistance Earth ground is to conduct a resistance test with a Meggar. All this is a a fancy meter and generator that sends hundreds / thousands of volts into the ground and measures what the return value / resistance is. Let's just say nobody does this kind of testing or is asking an arm and a leg to conduct such a test.

You can just purchase one or more ground rods and the required cable, bonding nut and drive the rods into the ground per the NEC as to how far they need to be. Doing so will reduce the grounding resistance no matter where you started. Say it was 50 Ohms and you drive another single rod into the ground its more likely (If tested) the resistance would drop to 30 - 25 Ohms immediately! 😀  You drive two ground rods evenly spaced per the NEC and its no doubt the ground resistance (When Measured) would be well below 10 - 5 Ohms.

Keeping in mind resistance is highly contingent on the type of soil, moisture / lack of, grounding type, and surface area being tapped into.

NOTE: I'm not sure why all of my posts are being held for review all the time. This always causes a late reply and solution being offered to the forum members. Let me know if you have more questions as it relates to SPD's. ✌️ 

Rock On . . .

[digigurl]

Apologies for my delayed response. Wow, that is a wealth of knowledge. I have to confess, the technical details go over my head, but I relayed your reply to the person who understands and will carry out the work for me. 

My posts are also delayed (although this post was late because I was recently side-tracked with deadlines). Perhaps it's a matter of SE resources. 

Thanks again. I greatly appreciate the time you spent to write a thorough reply!

Cheers!