# IEC vs DP contactors



## JRaef

In general, your observations are true when it comes to the contacts themselves but as to the "sturdier" aspect, not really. You are likely equating "sturdy" to the heft of the plastic bodies, springs and moveable parts. But that doesn't always equate to longevity. Ramblers were "sturdy" cars, but not many of them are still on the road compared to other cars of the same era.

DP for me stands for "Don't Purchase"... They are cheaply made, cheaply assembled, not really repairable (although some allow changing the contacts) and not designed to last. In fact their official name, Definite Purpose, is because they are sold to equipment manufacturers that want to supply the LEAST they can get away with and outlast their warranty, usually just 1 year. After that, they don't care.

In fact an often missed issue with DP is that they are *NOT UL listed*, so you can't use them by themselves (when/where UL listing is required). They are always UL Recognized Components (UR), which means they can legally ONLY be used as part of a listed assembly, i.e. the machine they came with. the only legitimate use for loose parts in the field is as 1-for-1 replacements of failed units, and even then the part number must be exact. Hardly anyone pays attention to that fact and vendors sell them with impunity, but it CAN burn you if an inspector is savvy enough. Most of the IEC contactors sold here are UL listed, so you can use them anywhere.

IEC contactors on the other hand might LOOK lighter and less hefty, but in fact the mechanical components are much more heavily engineered to last. Don't get me wrong, they are NOT the same as NEMA contactors in that regard, but there is a lot more too them than DP. Mechanically IEC contactors must last at least 10,000,000 operations and electrically at least 1,000,000 at their face value, up to the 10,000,000 if properly de-rated (using a complex system of investigation and calculation that few people understand). Again, DP is deigned to last a year, anything more is luck.

Lots of people still make DP contactors, but Furnas is no longer one of them. Siemens bought Furnas a long time ago and moved the mfg plant for DP from Iowa to Mexico, then Mexico was too expensive, so they moved it again to India, then India was too expensive and Siemens didn't want to have to deal with running a plant in China to stay competitive, so they sold the entire product line off to another company called MARS. All along the way the Furnas name was never changed because it was in some of the plastic molds, so even the new ones made in China still say Furnas on them, but they are not the same. All DP contactors are now made in China by the lowest bidders. If you get something that still says made in the USA, it is old stock.


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## 460 Delta

Yeah JRaef I know that Furnas is no longer and that CH, Arrow Hart, AB, and others made DP contactors, but the majority of them I come across are Furnas. I also know that IEC has a lot of engineering in it for longevity purportedly, but I see some level of engineering [Soviet Russian] in some of these DP contactors. I suppose they made up for inferior materials by using more of them.
This was more of me musing than anything else.


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## MTW

I would take a NEMA knockoff from China before I took anything IEC.


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## 460 Delta

MTW said:


> I would take a NEMA knockoff from China before I took anything IEC.


Yeah MTW, how long until we get hit with a flood of garbage imitation stuff made out of flammable material, I’m actually serious about this. The Chinese are assiduous copyists, using whatever junk materials they have on hand. 
On a lighter note, it will be a Eaton automation Alan Bradly or a Rokwell Hammer Cutler.


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## Going_Commando

JRaef said:


> In general, your observations are true when it comes to the contacts themselves but as to the "sturdier" aspect, not really. You are likely equating "sturdy" to the heft of the plastic bodies, springs and moveable parts. But that doesn't always equate to longevity. Ramblers were "sturdy" cars, but not many of them are still on the road compared to other cars of the same era.
> 
> DP for me stands for "Don't Purchase"... They are cheaply made, cheaply assembled, not really repairable (although some allow changing the contacts) and not designed to last. In fact their official name, Definite Purpose, is because they are sold to equipment manufacturers that want to supply the LEAST they can get away with and outlast their warranty, usually just 1 year. After that, they don't care.
> 
> In fact an often missed issue with DP is that they are *NOT UL listed*, so you can't use them by themselves (when/where UL listing is required). They are always UL Recognized Components (UR), which means they can legally ONLY be used as part of a listed assembly, i.e. the machine they came with. the only legitimate use for loose parts in the field is as 1-for-1 replacements of failed units, and even then the part number must be exact. Hardly anyone pays attention to that fact and vendors sell them with impunity, but it CAN burn you if an inspector is savvy enough. Most of the IEC contactors sold here are UL listed, so you can use them anywhere.
> 
> IEC contactors on the other hand might LOOK lighter and less hefty, but in fact the mechanical components are much more heavily engineered to last. Don't get me wrong, they are NOT the same as NEMA contactors in that regard, but there is a lot more too them than DP. Mechanically IEC contactors must last at least 10,000,000 operations and electrically at least 1,000,000 at their face value, up to the 10,000,000 if properly de-rated (using a complex system of investigation and calculation that few people understand). Again, DP is deigned to last a year, anything more is luck.
> 
> Lots of people still make DP contactors, but Furnas is no longer one of them. Siemens bought Furnas a long time ago and moved the mfg plant for DP from Iowa to Mexico, then Mexico was too expensive, so they moved it again to India, then India was too expensive and Siemens didn't want to have to deal with running a plant in China to stay competitive, so they sold the entire product line off to another company called MARS. All along the way the Furnas name was never changed because it was in some of the plastic molds, so even the new ones made in China still say Furnas on them, but they are not the same. All DP contactors are now made in China by the lowest bidders. If you get something that still says made in the USA, it is old stock.


Good info. We have used definite purpose contactors in the past for simple stuff, but man are they ever hokey.

IEC stuff has its place. For 5hp and smaller it's what we put in unless it is something that gets switched on and off a lot. We keep 32A contactors in stock so we are "over-building" for most things. Over 5 hp we put in Square-D NEMA stuff. It's just easier and cheaper for inventory to keep 32A contactors and a variety of overload units than to have bi-metallic heaters or solid state overloads in the multitude of sizes that are necessary to cover the bases for fractional up to 5 hp.


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## JRaef

460 Delta said:


> Yeah JRaef I know that Furnas is no longer and that CH, Arrow Hart, AB, and others made DP contactors, but the majority of them I come across are Furnas. ...


For a while back in the late 1980s I worked for Furnas as an app engineer, mostly for Nordic Soft Starters, but geographically they had me take care of anyone that was a big customer for anything. One such customer in Seattle that I did a lot of work for made commercial electric ovens, like the little ones you see in small restaurants that bake bread or pizza (they even made little rotating ovens for McDonalds that were going to make "McPizza" for an experiment that never took off). They bought 4,000 DP contactors per month for years, many of them ending up on service trucks as spare parts all over the world. So there are a LOT of them out there still.


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