swd circuit breakers
- Thread starter bjones930
- Start date
- Status
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Is the cover closed? If so I would say no but I may be wrong. I have never seen anyone wear arc flash to turn a breaker on with the cover on the panel.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
A SWD breaker is a 'standard' breaker that has passed life cycle tests for fluorescent ballast and tungsten light switching currents.
If it failed violently you would be exposed to the arc flash incident energy of the panelboard the breaker is mounted in.
The 70E seems to dodge these 'black and white' decisions on purpose. Your company needs to develop safe electrical work practices that address this situation. These practices may consider the risk associated with the switching task. The NFPA 70E committee has included informational language in the 2012 edition, stating they believe it is possible for under normal operating conditions properly installed and maintained equipment may not pose a hazard.
If it failed violently you would be exposed to the arc flash incident energy of the panelboard the breaker is mounted in.
The 70E seems to dodge these 'black and white' decisions on purpose. Your company needs to develop safe electrical work practices that address this situation. These practices may consider the risk associated with the switching task. The NFPA 70E committee has included informational language in the 2012 edition, stating they believe it is possible for under normal operating conditions properly installed and maintained equipment may not pose a hazard.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Jim there are thousand of individuals not associated with the industry who regularly turn these breakers on and off. I can't imagine expecting arc flash equipment for this. If so then they should not be allowed to be used as a switch.
zog
Senior Member
- Location
- Charlotte, NC
They sure do
"Properly installed and maintained" causes more problems than it solves IMO, according to who? Most guys I deal with everyday say thier "breakers work great, they never trip". The 70E does mention 70B and NETA standard, so that helps.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Is a 15 0r 20 amp breaker likely to cause injury when the panel cover is on?
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
It is not the breaker as much as it is the energy where the breaker is located. I have seen these small breakers installed in outdoor 600A service entrance panelboards as well as indoor 2-circuit loadcenters, one product two different amounts of risk
There is nothing written in NFPA70E or OSHA, that would prevent your company from making an assessment.
zog
Senior Member
- Location
- Charlotte, NC
Agreed, IR scan about covers it, I was just commenting on the new 70E verbage, not really refering to the OP.
zog
Senior Member
- Location
- Charlotte, NC
Yep, it seems this is the most common misconception when it comes to arc flash.
John120/240
Senior Member
- Location
- Olathe, Kansas
One important thing to remember "Never stand in front of the panel when operating breakers"
Stand off to one side and turn your head is the best pratice. How many store clerks pratice
these safety measures ??
- Location
- Massachusetts
If standing to the side is necessary the NEC should not allow us to use breakers as switches.
As you point out store clerks are not trained and will never be.
T
T.M.Haja Sahib
Guest
Small breakers also have fault current breaking capacity printed on them.As such,I wonder how they could have been installed without verification in outdoor 600A service entrance panel boards,where fault level would normally be much higher than their breaking capacity.
- Location
- Massachusetts
We would use breakers of proper fault current ratings.
- Location
- Illinois
- Occupation
- retired electrician
Its easy...you just take the breakers out of the box and install them. Many installers have no idea of what interrupting rating is required and just install whatever breaker they have that fits. Not all inspectors look for this, and there are many jobs done without permits or inspections.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
This is why the latest NEC now requires the available fault current to be put on the panel. Previous to this the installer might not know what to use. I have seen where it can take 10-20 man-hours spread over 2-3weeks to get available fault current information.
the blur
Senior Member
- Location
- cyberspace
a 2 pole switch rated breaker doesn't exist. It's called an HID rated breaker for metal halid lighting. most counter guys never heard of it. it's usually a special order.
but now, I do wonder if 70E will kill off the switch rated breakers, and you'll see typical wall switches mounted in 1900 boxes next to panels.
365 days x 10 years. so a breaker is operated 3650 times over a 10 year period..... is that the mfg rating?
a typical light switch gets used 10 zillion times over a 10 year period.
but now, I do wonder if 70E will kill off the switch rated breakers, and you'll see typical wall switches mounted in 1900 boxes next to panels.
365 days x 10 years. so a breaker is operated 3650 times over a 10 year period..... is that the mfg rating?
a typical light switch gets used 10 zillion times over a 10 year period.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
For what its worth, non-SWD breakers <100Aare tested for more than 10,000 total operations (no-load plus full load). Regardless what people say, it is all but impossible to 'wear out' a small molded case breaker in normal use. However, given the hundreds of thousand small breakers manufacturered each year, it is statistically possible some breakers will fail after a relatively few operations. And of course let's not forget the abused and misapplied breakers which can fail at any time.
T
T.M.Haja Sahib
Guest
The panel board with series rated circuit breakers is required to display the breaking capacity by the code.But what about the panel board with full rated breakers?
- Location
- Illinois
- Occupation
- retired electrician
All panels have to have their ratings marked on the nameplate. Additional labels are required for series rated systems. Jim was talking about the rule in 110.24 in the 2011 code that requires service equipment, other than in dwelling units, be marked with the available fault current. Not the rating of the panel and its breakers, but the amount of current that the utility could supply into a fault.
- Status