nema size 4 contactor clearance
- Thread starter gene_k
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Re: nema size 4 contactor clearance
Gene
Now that your post has been sitting here for a few days I thought I may as well put my two cents in it and maybe others will finally jump in too.
Have you considered an enclosure made and listed for that purpose? It may be a lot less grief as your time may be worth more than the cost of purchasing a suitable enclosure.
If you do want to consider your own enclosure the L-L, L-N, and L-G clearances must be maintained base on 600v which is a minimum of 1/4" as I recall but please verify that.
The wire bending space mist also be taken into consideration.
But, I still advise you to get an enclosure listed by the contactor manufacturer as the AHJ may be more agreeable to that.
What do you think?
Dave
Gene
Now that your post has been sitting here for a few days I thought I may as well put my two cents in it and maybe others will finally jump in too.
Have you considered an enclosure made and listed for that purpose? It may be a lot less grief as your time may be worth more than the cost of purchasing a suitable enclosure.
If you do want to consider your own enclosure the L-L, L-N, and L-G clearances must be maintained base on 600v which is a minimum of 1/4" as I recall but please verify that.
The wire bending space mist also be taken into consideration.
But, I still advise you to get an enclosure listed by the contactor manufacturer as the AHJ may be more agreeable to that.
What do you think?
Dave
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: nema size 4 contactor clearance
There are no NEC clearances for components. There are, however, wire bending requirements. All you need to do is allow the proper wire bending space, depending on your actual conductors, either straight in or at 90deg to the contactor terminals.
Personally, I would have no reluctance at all to using an IEC contactor instead of a NEMA size 4. I have done it for many years with no unexpected problems. Just remember to size the IEC device to the same amps as a NEMA size 4 and not just on horsepower.
There are no NEC clearances for components. There are, however, wire bending requirements. All you need to do is allow the proper wire bending space, depending on your actual conductors, either straight in or at 90deg to the contactor terminals.
Personally, I would have no reluctance at all to using an IEC contactor instead of a NEMA size 4. I have done it for many years with no unexpected problems. Just remember to size the IEC device to the same amps as a NEMA size 4 and not just on horsepower.
Re: nema size 4 contactor clearance
Thanks Jim, I though we could get this one jump started.
Should Gene elect to go with an IEC contactor which may in fact fit the existing enclosure, he should remember that IEC contactors applications are not as forgiving as the NEMAs are. Since IEC Standards do not define standard sizes an IEC rating indicates that a manufacturer or laboratory has evaluated the contactor to meet the requirements of a number of defined applications, or utilization categories.
IECs are very application sensitive as their life expectancy is rated based upon AC1,AC2,AC3,AC4, and AC15 duties.
I found the following link which should provide some insight into the proper application: A-B Bulletin 100-C Contactors
Thanks Jim, I though we could get this one jump started.
Should Gene elect to go with an IEC contactor which may in fact fit the existing enclosure, he should remember that IEC contactors applications are not as forgiving as the NEMAs are. Since IEC Standards do not define standard sizes an IEC rating indicates that a manufacturer or laboratory has evaluated the contactor to meet the requirements of a number of defined applications, or utilization categories.
IECs are very application sensitive as their life expectancy is rated based upon AC1,AC2,AC3,AC4, and AC15 duties.
I found the following link which should provide some insight into the proper application: A-B Bulletin 100-C Contactors
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: nema size 4 contactor clearance
Almost all IEC devices also carry a UL listing for specific horsepower. But the NEMA devices are grossly oversized compared to HP, which most people take to mean "more rugged".
A NEMA Size 1 contactor while listed for a 10HP 480V maxium actually is rated for 27A. If you chose a 25A minimum (instead of the suggested 18A) IEC contactor you should expect to get comparable perfomance on a 10HP 480V motor.
Almost all IEC devices also carry a UL listing for specific horsepower. But the NEMA devices are grossly oversized compared to HP, which most people take to mean "more rugged".
A NEMA Size 1 contactor while listed for a 10HP 480V maxium actually is rated for 27A. If you chose a 25A minimum (instead of the suggested 18A) IEC contactor you should expect to get comparable perfomance on a 10HP 480V motor.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Re: nema size 4 contactor clearance
for the vast majority of applications IEC contactors are a very economical and appropritae choice.
yes, you do have to think a little about your application, but you probably should do that anyway.
I would not and do not hesitate to use IEC contactors.
there are a few cases where I prefer nema starters, but they are few and far between.
as for buying the manufacturers enclosure, thats another story. its often more convenient to buy the starter with a disconnect switch and an enclosure all in one piece. usually it ends up costing you less to do it this way as well. by the time you figure out what size enclousre to buy, add in some kind of disconnect, etc, you might as well just order a combo staer, especially if its just a single unit.
for the vast majority of applications IEC contactors are a very economical and appropritae choice.
yes, you do have to think a little about your application, but you probably should do that anyway.
I would not and do not hesitate to use IEC contactors.
there are a few cases where I prefer nema starters, but they are few and far between.
as for buying the manufacturers enclosure, thats another story. its often more convenient to buy the starter with a disconnect switch and an enclosure all in one piece. usually it ends up costing you less to do it this way as well. by the time you figure out what size enclousre to buy, add in some kind of disconnect, etc, you might as well just order a combo staer, especially if its just a single unit.
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