AC spd protection ?

[Puckdrop 31]

A 200'amp 120/240 main panel with a whole house spd installed has a 30a 240v ac unit coming from this panel. There are other feeds to equipment that is not an issue at this time.

What is the best way to add spd protection to ac unit ? I cannot wire a separate spd to the 30amp CB feeding the ac unit. I don't believe wiring a spd to the ac'disconnect is a better solution.

I am trying to cascade spd protection to ac but can't come up with a simple way to do that. Any ideas will be a great help. TIA

 

[Little Bill]

A 200'amp 120/240 main panel with a whole house spd installed has a 30a 240v ac unit coming from this panel. There are other feeds to equipment that is not an issue at this time.

What is the best way to add spd protection to ac unit ? I cannot wire a separate spd to the 30amp CB feeding the ac unit. I don't believe wiring a spd to the ac'disconnect is a better solution.

I am trying to cascade spd protection to ac but can't come up with a simple way to do that. Any ideas will be a great help. TIA

If there is a SPD in the panel that is feeding the AC unit, why do you want another?

Some panel brands have SPD breakers that also are used for branch circuit protection. I know Eaton CH does, probably others.

 

[Puckdrop 31]

If there is a SPD in the panel that is feeding the AC unit, why do you want another?

Some panel brands have SPD breakers that also are used for branch circuit protection. I know Eaton CH does, probably others.

There are other loads in panel,electric water heaters, air handler, sub panel. It's recommended to have layers of protection. The ac unit has only first layer protection.'This is why I ask my question.
Thanks Bill

 

[TwistLock]

Was just working with a filled up Siemens panel today, no space so their QSA 'SPD/Breaker' style, that Little Bill mentions, was considered as an option. In Siemens case though the Rep said they’re not quite the level of protection as their QSPD (SPD only) in-panel versions are, but still a great option.
HVAC equipment required SPD for warranty so I opted to slap a Mars 83905 on the side of the disco.

 

[David Castor]

The best location for the surge protection is as close as possible to the equipment being protected. For an outdoor a/c compressor or heat pump, the most effective location is at the local disconnect.

 

[Puckdrop 31]

Thanks for all replys and both obtions

 

[Knightryder12]

There are other loads in panel,electric water heaters, air handler, sub panel. It's recommended to have layers of protection. The ac unit has only first layer protection.'This is why I ask my question.
Thanks Bill

From what I know, its really a waste of money to protect the downstream items if the panel that its fed from already has an SPD. Who is telling you that layers is better? The manufacturer of the SPD? if so, they just want to sell more SPDs.

 

[Puckdrop 31]

From what I know, its really a waste of money to protect the downstream items if the panel that its fed from already has an SPD. Who is telling you that layers is better? The manufacturer of the SPD? if so, they just want to sell more the

 

[TwistLock]

...was told by Siemens that if you have SPD at service but also you wish additional SPD at sub-panel that terminating to the ground bar (rather than white wire to neutral bar), in sub, offers increased protection (?)

 

[LarryFine]

Cascaded protection is better for external and internal disturbances.

At the main service, at sub-panels, and at sensitive loads.

Check your connected-equipment warranties, especially the claim process.

 

[Little Bill]

From what I know, its really a waste of money to protect the downstream items if the panel that its fed from already has an SPD. Who is telling you that layers is better? The manufacturer of the SPD? if so, they just want to sell more SPDs.

It has been shown that if you have a whole house SPD, sometimes the clamping action can still allow a small amount of surge voltage/current to pass through. Sensitive electronics, such as TV, computer, some refrigerators, etc. benefit from having point of use protection in addition to the whole house SPD. Not some cheezy power strip, but an actual SPD in receptacle form. They make receptacles with SPD built in.
So yes, layered protection is better.

 

[Puckdrop 31]

From what I know, its really a waste of money to protect the downstream items if the panel that its fed from already has an SPD. Who is telling you that layers is better? The manufacturer of the SPD? if so, they just want to sell more SPDs.

There has been talk from manufactory and other of sources that there is a need for surge protection for inside and outside this is why cascading protection is suggested.

 

[Rick 0920]

IMO, an SPD is like buying an extended warranty for your car, or buying an overpriced item because it comes with a guarantee. You could have all the surge protection that money can buy, but if lightning wants your tv, or your AC unit, or your computer, it's going to take it. SPD's are not lightning arrestors. They both operate by using MOV's (Multiple Oxide Varistors) that will clamp or shunt with excess surges and some nearby lightning strikes that cause transient voltages. Some of my old customers and friends that want me to install them at their services because they've heard that they are now required, I do it for them. But I don't guarantee anything. I'm not educated on the subject enough to tell them exactly what they will or will not do, but I do tell them that if your electronics take a direct hit from lightning, they're gone!

 

[Knightryder12]

It has been shown that if you have a whole house SPD, sometimes the clamping action can still allow a small amount of surge voltage/current to pass through. Sensitive electronics, such as TV, computer, some refrigerators, etc. benefit from having point of use protection in addition to the whole house SPD. Not some cheezy power strip, but an actual SPD in receptacle form. They make receptacles with SPD built in.
So yes, layered protection is better.

I just don't buy it. If lightning wants anything, SPD or not, its gone. I don't care how many SPDs or their location.

 

[hornetd]

From what I know, its really a waste of money to protect the downstream items if the panel that its fed from already has an SPD. Who is telling you that layers is better? The manufacturer of the SPD? if so, they just want to sell more SPDs.

The layered protection approach is the recommendation of the National Institute of Standards and Technology (NIST). They did a lot of experimentation before they published that advice in a pamphlet I believe they called "Surges Happen."

 

[Little Bill]

I just don't buy it. If lightning wants anything, SPD or not, its gone. I don't care how many SPDs or their location.

I never said anything about lightning. I know that a direct hit and all bets are off. I was talking about surges from the grid, or even your own service. I will say that lightning may travel a ways and the effects could be mitigated due to the distance. A SPD may help with this as well.

 

[readydave8]

I just don't buy it. If lightning wants anything, SPD or not, its gone. I don't care how many SPDs or their location.

Why wear a seat belt if some wrecks will kill you anyway?

 

[Flicker Index]

From what I know, its really a waste of money to protect the downstream items if the panel that its fed from already has an SPD. Who is telling you that layers is better? The manufacturer of the SPD? if so, they just want to sell more SPDs.

The panel SPD is intended to absorb external surge. Surge often originates within the building. If you pack a hammer with eggs inside the box, it will likely break no matter how well you protect it outside the box. A layered approach reduces the surge by the hammer, and another layer reduces the impact from the hammer on the eggs.

There was a time in history when lighting devices like HID and fluorescent (hollow glass tubes filled with mercury vapor) were driven by nothing but magnet wires wrapped around steel. Around the turn of the millennium, electronic ballasts became common. Early electronic ballasts, especially those used on 277/480 system were very vulnerable, because the semiconductor parts couldn't take the surge present on circuit the same way as core and coil ballast.

Ballasts were later designed with internal surge protector intended to have absorption capacity that is expected to be needed over the design life of the ballast. External surge protector at the circuit, or likely surge producing load reduces the wear on SPD inside local devices.

You will find an MOV (surge absorber element) across the line in many individual LED screw in bulbs so the fragile LED ballast is not fried by ordinary surge.

 

[tom baker]

Cascaded protection is better for external and internal disturbances.

At the main service, at sub-panels, and at sensitive loads.

Check your connected-equipment warranties, especially the claim process.

Correct. The SPD at the service reduces the surge, and the use the impedance of the building to further reduce for a Type 3 SPD

 

[tom baker]

From what I know, it’s really a waste of money to protect the downstream items if the panel that its fed from already has an SPD. Who is telling you that layers is better? The manufacturer of the SPD? if so, they just want to sell more SPDs.

“More is better, you get what you pay for” Mike Holt.
I went to several seminars by Leviton in the mid 90s, they recommended a main SPD and then point of use SPDs. They had test results from this approach.