Electrically vs. Manually operated circuit breaker
- Thread starter faresos
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zog
Senior Member
- Location
- Charlotte, NC
E/O allows for remote closing and tripping and also has a motor to charge the springs
M/O has no remote functions (But may have a shunt trip) and requires the operator to manually charge the closing springs using a handle.
M/O has no remote functions (But may have a shunt trip) and requires the operator to manually charge the closing springs using a handle.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
With regards to what specific application? Please give details of what you have and why you need to decide which way to go.
Or is this a homework question?
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
Some smaller breakers are also operated by a solenoid (SOB's), such as those manufactured by CH/Westinghouse. Not all electrically operated breakers are done so because of size, several manufactures offer breakers in the 15-20 amp range for energy management control. Some are very large, and are used as transfer switches, but as Jaref has stated there are many uses and types.
I'm working on a specifications for switchboard (1600A @ 480/277V) and came cross E/O & M/O molded case circuit breaker for main and branch feeders. This job is for a warehouse and I'm more leaning toward the M/O since there is no shunt trip required for this specific project unless the E/O has more benefits that would be used in the future for any reason
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
The only time I have ever run across motor operated breakers was for controlling medium voltage motors. They were using them like motor starters.
zog
Senior Member
- Location
- Charlotte, NC
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
The only time I would use EO MCCBs is when there is an absolute need to reclose the breaker remotely, as in no direct human contact available. In general it's a really bad idea because people tend to get lazy and do things they shouldn't do, such as reclose into a fault because they were too lazy to check it out first. When you have your hand on the operating mechanism to do it manually, you tend to think it through a little longer. Pushing a button in a control room 100 yards or 5 miles away lends itself to the lazy method.
They are also very very expensive and it increases the likelihood of needing repair and maintenance, something people are not used to having to do on MCCBs.
T
T.M.Haja Sahib
Guest
There may be a relation between existing fault level at the breaker and the choice between MO and EO.Need to be checked up.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
I am almost afraid to ask, but just why would the fault level matter any? nd just what fault level are you referring to?
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
You should be afraid to ask, now we will launch into another 100+ post thread....
zog
Senior Member
- Location
- Charlotte, NC
Got my popcorn ready, this should be interesting.
I have a pretty good guess to where he is going with this, but I have thought the same before and am always way off with him.
T
T.M.Haja Sahib
Guest
100+ threads or not depends on your interest level on the subject for example.
milemaker13
Senior Member
- Location
- Suburbs of Chicago
In the old computer server room the main CB in the panel was electrically controlled. The reason was so there could be an E-stop at the door going out. I guess if there was a fire or some other emergency in that room, you would hit the estop on your way out. There was a key operator next to the Estop that would re- energize the panel. Had us scratching our heads for a moment or two.
rcwilson
Senior Member
- Location
- Redmond, WA
Electrically operated breakers allow remote operation to keep an operator away from the front of the breaker.
But obviously, EO also requires control power. That usually comes from a Control Power Transformer (CPT) tapped ahead of the Main in the switchgear if it is AC powered or a battery bank if DC control is used. If the breakers need to operate when the utility power is down, the battery bank is required. Control power also means extra wiring and costs.
For a warehouse switchboard, I would use manually operated, molded case switchboard breakers.
But obviously, EO also requires control power. That usually comes from a Control Power Transformer (CPT) tapped ahead of the Main in the switchgear if it is AC powered or a battery bank if DC control is used. If the breakers need to operate when the utility power is down, the battery bank is required. Control power also means extra wiring and costs.
For a warehouse switchboard, I would use manually operated, molded case switchboard breakers.
maghazadeh
Senior Member
- Location
- Campbell CA
Last time I used the Electrically Operated Breakers of small 20A frame was in a panel feeding sound systems. (Sequence Operation) to avoid system screaming.
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