Surge supressor protection

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delfadelfa

Member
Location
Cincinnati, OH
I have a customer that owns a dental office and wants to protect his equipment with a panel surge supressor. This panel also has generator backup with a 20KW Generac that feeds a 200 amp transfer switch which then feeds the 200 amp cutler hammer sub panel. I have installed the $50 panel mounted surge supressors in residential homes but I want to make sure I do this right because he has some expensive 240 volt x-ray equipment and I don't want any call backs. Any suggestions on protection? Voltage conditioners? Thanks
 

beanland

Senior Member
Location
Vancouver, WA
No Guarantee

No Guarantee

It almost sounds like you will guarantee that his equipment is safe with the surge protector installed. No surge protector can prevent equipment damage. Surges are complex high-frequency events. The more surge protection the better. The best surge protector is located at the load where the voltage spike will be highest. I have never thought much of panel-mounted units because they are on the line and have long leads to ground and bus; both which lead to higher voltages across them during events. However, using a panel unit plus an additional unit at the equipment cannot hurt, but still no guarantees.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
It almost sounds like you will guarantee that his equipment is safe with the surge protector installed. No surge protector can prevent equipment damage. Surges are complex high-frequency events. The more surge protection the better. The best surge protector is located at the load where the voltage spike will be highest. I have never thought much of panel-mounted units because they are on the line and have long leads to ground and bus; both which lead to higher voltages across them during events. However, using a panel unit plus an additional unit at the equipment cannot hurt, but still no guarantees.

I think you are sort of right here.

The surge protectors installed closer to the service point only work at higher voltage levels than the ones designed to be installed downstream.

I would put one at the service panel and one at the point of use.

You cannot prevent damage from transients, but you can reduce the risk.
 

kwired

Electron manager
Location
NE Nebraska
I agree with what has been said so far.

Is the transfer of this generator automatic?

Is using the X-ray equipment when on standby power a very good idea? Small generators are not very stable voltage source to begin with, switch a large enough load and you will have much more transient voltages (high and low) than you will on utility power.
 

delfadelfa

Member
Location
Cincinnati, OH
The transfer switch is automatic with a 10 second delay. I found a Cutler Hammer breaker type surge suppressor for 100 bucks. I guess I will install that and tell him that there is no guarantee that this supressor will protect the $30K board on his Panoramic x-ray equipment.
 

delfadelfa

Member
Location
Cincinnati, OH
I did get some feedback from another board and their suggestion was to install a UPS system on the equipment. This would not only protect the equipment from the power interuption when the generator is starting up but also protection against voltage spikes, over voltage, high frequency transient or oscillation, and harmonic distortion. Looks like I'll be giving him an estimate on a UPS system....
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I did get some feedback from another board and their suggestion was to install a UPS system on the equipment. This would not only protect the equipment from the power interuption when the generator is starting up but also protection against voltage spikes, over voltage, high frequency transient or oscillation, and harmonic distortion. Looks like I'll be giving him an estimate on a UPS system....
I think your best bet would be to talk to the equipment manufacturer directly first. They probably have their own ideas about how best to protect this type of equipment.
 
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