Switchgear vs. Switchboard
- Thread starter jkim780
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Re: Switchgear vs. Switchboard
In my personal lexicon switchgear would be anything that goes in a switchboard. The switchboard would be the vessel, and the switchgear would be the contents of the vessel.
Switchgear= circuit breakers, fuses, switches, etc.
[ September 30, 2003, 04:53 PM: Message edited by: awwt ]
In my personal lexicon switchgear would be anything that goes in a switchboard. The switchboard would be the vessel, and the switchgear would be the contents of the vessel.
Switchgear= circuit breakers, fuses, switches, etc.
[ September 30, 2003, 04:53 PM: Message edited by: awwt ]
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Re: Switchgear vs. Switchboard
From article 100 (always a good place to start)
From article 100 (always a good place to start)
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- Massachusetts
Re: Switchgear vs. Switchboard
Do not take this as an official definition.
When I hear switchgear I think of voltages, above 600 volts. In large commercial work you may have 13.8 KV coming inside the building, many times two circuits from different POCO supplies so if one fails the other takes over the load automatically or manually.
In this gear is high voltage breakers, current and voltage meters, ground fault detection equipment and meters for billing.
When I hear switch board I think voltages under 600 volts and basically a bunch of panels mounted in a common enclosure.
But that is just my experience, it is certainly not the only way to describe this equipment.
-Bob
Do not take this as an official definition.
When I hear switchgear I think of voltages, above 600 volts. In large commercial work you may have 13.8 KV coming inside the building, many times two circuits from different POCO supplies so if one fails the other takes over the load automatically or manually.
In this gear is high voltage breakers, current and voltage meters, ground fault detection equipment and meters for billing.
When I hear switch board I think voltages under 600 volts and basically a bunch of panels mounted in a common enclosure.
But that is just my experience, it is certainly not the only way to describe this equipment.
-Bob
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Re: Switchgear vs. Switchboard
Thanks for nailing it down with an NEC cut/paste. Your answer fits the question better.
If you take "Metal-Enclosed Power" out of the term then my description holds up. In the trades switchgear is used as a generic term.
Thanks for nailing it down with an NEC cut/paste. Your answer fits the question better.
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Re: Switchgear vs. Switchboard
Simple answer:
Switchgear is built to ANSI standards (C37C37.20.2), although UL now has some input. Typical requirements include: Drawout breakers, fully compartmented construction (grounded metal barriers around all live parts), automatic shutter, insulated bus bars, mechanical interlocks.
Switchboards are built to UL standards (UL891). Basically these are large panelboards.
Simple answer:
Switchgear is built to ANSI standards (C37C37.20.2), although UL now has some input. Typical requirements include: Drawout breakers, fully compartmented construction (grounded metal barriers around all live parts), automatic shutter, insulated bus bars, mechanical interlocks.
Switchboards are built to UL standards (UL891). Basically these are large panelboards.
ron
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Re: Switchgear vs. Switchboard
The ANSI and UL standards to which each is built is the key.
For the most part, they are becomming more and more inetrchangable, as you can now get drawout breakers, 30 cycle short circuit ratings and 200kAIC on switchboards where you would have been relegated to switchgear in the past.
The ANSI and UL standards to which each is built is the key.
For the most part, they are becomming more and more inetrchangable, as you can now get drawout breakers, 30 cycle short circuit ratings and 200kAIC on switchboards where you would have been relegated to switchgear in the past.
Re: Switchgear vs. Switchboard
Your answers helped me a lot. But there is still one thing that I don't understand. If they are interchangable and perform a lot alike, why do they have different standard at first place? What would be the "rule of thumb" or the best example application that you have to use a switchgear instead of a switchboard?
Your answers helped me a lot. But there is still one thing that I don't understand. If they are interchangable and perform a lot alike, why do they have different standard at first place? What would be the "rule of thumb" or the best example application that you have to use a switchgear instead of a switchboard?
ron
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Re: Switchgear vs. Switchboard
When specified and custom ordered, they can be configured similarly.
In their standard product lines, they are different, as made clear by the different standard listings UL and ANSI.
IMHO, I specify switchgear if I need 100 or 200KAIC ratings with an ampacity of larger than 1600A. I spec Switchboards below that, to approx 800A. Then 800A and below, I spec panelboards.
There is no exact science, as long as you spec the items you want and verify you get them via shop drawings.
When specified and custom ordered, they can be configured similarly.
In their standard product lines, they are different, as made clear by the different standard listings UL and ANSI.
IMHO, I specify switchgear if I need 100 or 200KAIC ratings with an ampacity of larger than 1600A. I spec Switchboards below that, to approx 800A. Then 800A and below, I spec panelboards.
There is no exact science, as long as you spec the items you want and verify you get them via shop drawings.
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- Wisconsin
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- PE (Retired) - Power Systems
Re: Switchgear vs. Switchboard
Switchboards are the common item unless the special features of switchgear are needed.
Reasons to use switchgear include: voltages above 600V; compartmentalized construction for routine work on or entry into energized gear (i.e large industrials); special metering or relaying (i.e. paralleling equipment); and because "grandpa" used it.
Switchboards are the common item unless the special features of switchgear are needed.
Reasons to use switchgear include: voltages above 600V; compartmentalized construction for routine work on or entry into energized gear (i.e large industrials); special metering or relaying (i.e. paralleling equipment); and because "grandpa" used it.
BAHTAH
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Re: Switchgear vs. Switchboard
While there are overlapping features between switchboards and switchgear there are significant differences that effect which product would be best for specific applications. There is not enough room here to go into all the specific features of each but here are some things to think about. Switchboards in general are used with distribution breakers that are group mounted meaning they are like in panelboards installed next to one another. The ability to withstand fault currents is less than that of switchgear. Switchboards typically have a maximum feeder breaker size of 1200amps. switchboards are typically used for service and distribution in facilities where reliability is not a major concern to safety or production. Switchboards are a flexible product with many good applications but basically of lighter construction than switchgear. Switchgear can withstand higher fault levels typically a 30 cycle withstand rating. Switchgear typically uses individually mounted distribution breakers which are or can be drawout construction allowing for servicing and testing. Switchgear is typically found in installations where reliability is desired or loads are frequently switched such as manufacturing, computer facilities, hospitals etc. The insulated and isolated bus construction as well as compartmentalization of breakers combined with higher withstand ability makes switchgear a more reliable and longer lasting product than switchboards. If you are interested let me know and I can fax you a copy of things to consider in the application of switchboards and switchgear. I look at it like the difference bewteen Loadcenters and Panelboards, they are similar and the NEC really makes no specific mention of the two products separately but they each have issues when it comes to application.
[ October 01, 2003, 11:54 AM: Message edited by: grant ]
While there are overlapping features between switchboards and switchgear there are significant differences that effect which product would be best for specific applications. There is not enough room here to go into all the specific features of each but here are some things to think about. Switchboards in general are used with distribution breakers that are group mounted meaning they are like in panelboards installed next to one another. The ability to withstand fault currents is less than that of switchgear. Switchboards typically have a maximum feeder breaker size of 1200amps. switchboards are typically used for service and distribution in facilities where reliability is not a major concern to safety or production. Switchboards are a flexible product with many good applications but basically of lighter construction than switchgear. Switchgear can withstand higher fault levels typically a 30 cycle withstand rating. Switchgear typically uses individually mounted distribution breakers which are or can be drawout construction allowing for servicing and testing. Switchgear is typically found in installations where reliability is desired or loads are frequently switched such as manufacturing, computer facilities, hospitals etc. The insulated and isolated bus construction as well as compartmentalization of breakers combined with higher withstand ability makes switchgear a more reliable and longer lasting product than switchboards. If you are interested let me know and I can fax you a copy of things to consider in the application of switchboards and switchgear. I look at it like the difference bewteen Loadcenters and Panelboards, they are similar and the NEC really makes no specific mention of the two products separately but they each have issues when it comes to application.
[ October 01, 2003, 11:54 AM: Message edited by: grant ]
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