Why does 277/480 cost so much?

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olsondavidj said:
Big discount schedules go to people who move product; it's not arbitrary. Maybe they don't buy bulk on every PO, but these sorts of buyers regularly send POs over and at the end of the year, they've bought a ton of product. You can bet money that if you get a good multiplier on something, and then one year you migrate to something else, you'll lose your multiplier. Might take a bit, but your distributor will catch on eventually.

But of course that's not the only thing that goes in to it. If you buy a thousand breakers a year, your distributor will probably cut you a deal on conduit too even if you only buy 50 ft a year. May not be much, but it'll be better than street price. They have an interest in keeping you as a customer. If you start looking elsewhere, who knows what deals you can find, and suddenly your old distributor doesn't get POs anymore.

Also, it depends on your market. My last company got a crazy discount on proximity sensors because they were headquartered in the Detroit area, so there's a TON of volume moving through that area for all the auto plants and machine builders, which means there's a TON of competition for that business. My local rep down here said he'd never seen a discount that steep in this area.
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I'll agree here in part- if not almost in full- you make a good point. :)
 
mbrooke said:
I've spoken to people who've said breakers cost pennies to make- even the big amp frame versions are in the dollars.

I'm convinced that we could safely use 240 volt panels boards on 277/480 without any hazard. Lets not kid ourselves that when you buy 480 volt gear you are actually buying a piece of 600/1000 volt gear with 6x transient withstand.
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No, not really. There are two voltage classes within LV gear,; 300V and 600V, and they have to do with L-L separation and dielectric isolation. Anything with a L-L potential of over 300V requires 1" of continuous surface area between poles, 1/2" of air gap, whichever is greater. You can't have 277V without having 480V L-L, so it requires the higher separation. In addition these is more mechanical energy in a fault as the voltage goes up so the withstand rating requires more internal structure strength. This is also why you cannot use a "slash rated" 480/277V rated breaker on a 480V delta system (a relatively new development in industry); the L-G potential could be 480V in the delta system, so again, more mechanical energy in trying to interrupt the fault.
 
Jraef said:
No, not really. There are two voltage classes within LV gear,; 300V and 600V, and they have to do with L-L separation and dielectric isolation. Anything with a L-L potential of over 300V requires 1" of continuous surface area between poles, 1/2" of air gap, whichever is greater. You can't have 277V without having 480V L-L, so it requires the higher separation. In addition these is more mechanical energy in a fault as the voltage goes up so the withstand rating requires more internal structure strength. This is also why you cannot use a "slash rated" 480/277V rated breaker on a 480V delta system (a relatively new development in industry); the L-G potential could be 480V in the delta system, so again, more mechanical energy in trying to interrupt the fault.
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Then why does the same 300 volt gear (limited to 240 volts here) get a 416 volt L-L approval outside the US? Either that said panelboards and load centers are 600V?
 
mbrooke said:
Then why does the same 300 volt gear (limited to 240 volts here) get a 416 volt L-L approval outside the US? Either that said panelboards and load centers are 600V?
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Different rules outside of North America... Plus, they NEVER have Delta power systems, they are ALWAYS Wye (what they call Star). So a 415V system is ALWAYS 415Y240V and it is never more than 240V L-G. But when you buy those IEC breakers that were designed for 415Y240V and use them here on 480V, you usually have to buy extra "phase barriers" for them to pass UL because of the clearances issues.

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Jraef said:
Different rules outside of North America... Plus, they NEVER have Delta power systems, they are ALWAYS Wye (what they call Star). So a 415V system is ALWAYS 415Y240V and it is never more than 240V L-G. But when you buy those IEC breakers that were designed for 415Y240V and use them here on 480V, you usually have to buy extra "phase barriers" for them to pass UL because of the clearances issues.

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In other words L-G also takes a factor?


So therefore, am I correct to say this:

Lets not kid ourselves that when you buy 480 volt gear you are actually buying a piece of 600/1000 volt gear with 6x transient withstand.
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Not so much challenging you as trying to see if my understanding is right.
 
mbrooke said:
...So therefore, am I correct to say this: ....
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mbrooke said:
.... Lets not kid ourselves that when you buy 480 volt gear you are actually buying a piece of 600/1000 volt gear with 6x transient withstand.
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Well, not really:
"480/277" cannot be used on "480V" (ungrounded or HRG).
"480V" cannot be used on "575V". "600V" can.​

I'm pretty sure everybody already knew this.
 
mbrooke said:
No- but if you go to the same store I don't think one customer should get more of a discount and the other less outside of coupons or general sales applicable to everyone.
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I'm sure you are aware that if you fly on an airplane, everybody has a different ticket price even though the seats are all the same (in each section).
 
Coppersmith said:
I'm sure you are aware that if you fly on an airplane, everybody has a different ticket price even though the seats are all the same (in each section).
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retirede said:
And consider that no 2 people ever paid the same price for the exact same new car.
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Sure. But lets say the price is being inflated like prescription meds. Wouldn't a media frenzy follow?
 
mbrooke said:
.... assuming L-G voltages will be the same as L-L voltages which was true decades ago more often then not.
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Absolutely not true. There has always been a difference in listing for L-G (e.g. 480Y/277V only) versus L-L (e.g. 480V)

I have 'lighting' panelboard data sheets from more than 69 years ago which clearly state certain products were limited to a maximum of 277V.
 
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