installing a type 1 spd on a 3 phase 400amp service

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ctaylo360860

ctaylo360860

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I'm trying to get an understanding on how I can install type one spd into a 400amp 3 phase service... I was hoping to put the spd in before the main disconnect, but i wasn't sure how exactly I would achieve this... The other plan I had is put a 30 amp 3 pole breaker in the main panel and feed # 10 copper to the spd. This is what square d recommended. here is the link. https://www.se.com/us/en/faqs/FA301285/

here is the spd SSP04EMA24 https://www.se.com/us/en/product/SS...gic-240ka-480y-277-vac-3-phase-4-wire-nema-1/

any and all help is greatly appreciated thank you in advance!

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qcroanoke said:

This is the instruction manual. You can hook it in front of the main. (see page 7) We use C-taps. but if your feed is parallel I'm not sure how you would do that...
you can also use breakers on the load side of the main. Size of breaker would depend on the size of the wire I assume.
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If you are going to do that, you might as well get the one that connected directly to the panelboard bus.
 
The problem with putting it ahead of the main, is it will require a utility shutdown WHEN, not if, it is replaced. Most engineers spec it off a breaker. Some gear manufacturers will pre wire it to a disconnect built into the gear for maintenance.
 
Is there any pros or cons anyone sees to having it before the main vs after the main? besides when it is installed , or needs replaced the utility would have to be involved.

Im thinking my best option for this spd will be to feed it off of a 30 amp breaker.
hillbilly1 said:
The problem with putting it ahead of the main, is it will require a utility shutdown WHEN, not if, it is replaced. Most engineers spec it off a breaker. Some gear manufacturers will pre wire it to a disconnect built into the gear for maintenance.
Click to expand...
That makes sense. I have had to replace spd in everyone of our motor control centers for our grain facility, and i'm pretty sure they're all like this..
 

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qcroanoke said:

This is the instruction manual. You can hook it in front of the main. (see page 7) We use C-taps. but if your feed is parallel I'm not sure how you would do that...
you can also use breakers on the load side of the main. Size of breaker would depend on the size of the wire I assume.
Click to expand...
Thank you, looks like I should have gotten a different model if I was going to put it ahead of the service disconnect. The runs are parallel and its a 400 amp breaker so i don't think id be able to feed my spd and still have the wires protected. since I think the biggest the lugs will take on spd is 2/0. You are correct. Schneider recommends a 30a breaker using # 10. notes say if connected to a separate dedicated branch circuit, the ocpd setting must be selected to protect the conductors feeding the SPD. Thanks for the reply!
 
ctaylo360860 said:
Thank you, looks like I should have gotten a different model if I was going to put it ahead of the service disconnect. The runs are parallel and its a 400 amp breaker so i don't think id be able to feed my spd and still have the wires protected. since I think the biggest the lugs will take on spd is 2/0. You are correct. Schneider recommends a 30a breaker using # 10. notes say if connected to a separate dedicated branch circuit, the ocpd setting must be selected to protect the conductors feeding the SPD. Thanks for the reply!
Click to expand...
You can often get lugs for MCCBs that have a threaded hole on them to add a small gauge tap.

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