Heavy Duty or General Duty switches
- Thread starter Woodyz
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mdshunk
Senior Member
- Location
- Right here.
It's more helpful to look at the switches ampre rating and horsepower rating, and pay less attention to what the marketing people might call the switch.
e57
Senior Member
- Location
- San Francisco, CA
IMO a general duty switch would be fine - as (it sounds as if) you would not be generally connecting under load situations. Which would require a much faster acting spring loaded mechanism to snap the contacts into place, and a much higher contact rating. And often will have chambers to contain the initial arc.
In a heavy duty switch, when operating it - you'll notice you are charging a spring, and triggering a release to SLAM the contacts fully shut as fast as possible. In a general duty, (Meant to connect under light/no load conditions) the mechanism will be much slower, and allow a longer time of partial contact. But still must be rated to handle the high amperage of motor starting while closed.
Also, FYI it may be difficult to find a general duty switch rated for over 240V... As over that voltage an arc can be self-sustaining IMO.
In a heavy duty switch, when operating it - you'll notice you are charging a spring, and triggering a release to SLAM the contacts fully shut as fast as possible. In a general duty, (Meant to connect under light/no load conditions) the mechanism will be much slower, and allow a longer time of partial contact. But still must be rated to handle the high amperage of motor starting while closed.
Also, FYI it may be difficult to find a general duty switch rated for over 240V... As over that voltage an arc can be self-sustaining IMO.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
It is kind of like asking about SO and SJO cords.
Heavy duty switches are normally available up to 600V. They also normally come in more styles of enclosures (like NEMA 7/9) as well as have more accessories.
Heavy duty switches are normally available up to 600V. They also normally come in more styles of enclosures (like NEMA 7/9) as well as have more accessories.
charlie tuna
Senior Member
- Location
- Florida
the general duty switch is much cheaper than the heavy duty. comparing the two ,side by side, you can understand why the price difference. two main issues come to my mind when specifying a heavy duty or general duty switch. type of load such as motor loads and how close the maximum load is to the "full load" rating of the switch. an example would be an elevator disconnect. this is a motor load that is continually cycling. if a general duty switch is used and close to the switch's maximum current carrying rating -- it's life of this switch will be shortened. if the load was only 50 per cent of the rating of the general duty switch it may function without a problem. my $.02
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
I have found that most disconnects that are marketed as heavy duty have a 600V rating and have a slightly higher withstand rating than a standard duty.
JohnJ0906
Senior Member
- Location
- Baltimore, MD
Are they both rated to be service disconnects ?
mdshunk
Senior Member
- Location
- Right here.
I think so. The little wee 30 amp one's I use for billboard services are so rated.JohnJ0906 said:
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