blupony96
Member
- Location
- Benld, IL USA
I need to install a 208V 1p breaker for a server. The service is a 208V 3p. I am stumped as to which breaker to use. Can I just use a 120/240V breaker or is there something I am missing?
Never worked with 208V!
- Thread starter blupony96
- Start date
- Status
- Location
- Massachusetts
I looked at your profile and am curious if your area allows you to do this work.
That aside if you need 208 volts from a 208Y/120 supply you will need a 2 pole breaker not a single pole. The fact you do not know that re-enforces my concerns of your qualifications to do this work.
(I answered in hopes that you were asking from a "Technical" standpoint in "assisting engineers" as in your profile. ) I would have to agree with Iwire and
emphasize from the nature of your question you do not need to be performing any installations.
emphasize from the nature of your question you do not need to be performing any installations.
growler
Senior Member
- Location
- Atlanta,GA
I agree with Iwire that you are probably not qualified to do this work. But don't feel bad because most of us are not qualified to do your job either. I would suggest that you get a qualified electrician because when I install this sort of equipment I almost never get the correct information furnished to me and have to visit the job site to determine what is really needed.
- Location
- Massachusetts
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
It is possible the OP is not looking to do the actual installation, but rather needs to select and specify a device on a set of construction documents.
- Location
- Massachusetts
Of course it is possible, but the first four words of their post suggest otherwise.
blupony96
Member
- Location
- Benld, IL USA
Everyone is correct about my qualifications. I am NOT doing the installation! This type of work is outside my scope. I would love to do the installation, but finding an apprenticeship around here is very hard. What I am trying to accomplish is create the proper documents and acquire the materials so the installation goes off without a hitch.
Now, I have phrased my question improperly. I need assistance selecting a 2 pole breaker. I am looking at 120/240V 30A GE THHQB and THQB breakers. I can't find the information that distinguishes the difference between the 2. Can someone suggest/define which breaker would be correct to use?
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
The main difference between a EE degree and a EET degree is that the EET gets more time in the lab with test equipment, and winds up with more hands-on experience than a EE would ever get. A EET is more qualified than a EE to carry a tool belt. As to whether the local laws and the nature of the task would enable a EET to perform an installation task, or whether a licensed electrician is needed, that is more than I can address.
It seems to me that the basic question comes down to the compatibility of the panel and the proposed breaker. You say that you can't find a 2-pole breaker that is rated for 208 volts. That would surprise me. But perhaps the manufacturers rate their breakers at 240 volts, and allow them to be used in either a 208 volt panel or a 240 volt panel. Can anyone address this question?
It seems to me that the basic question comes down to the compatibility of the panel and the proposed breaker. You say that you can't find a 2-pole breaker that is rated for 208 volts. That would surprise me. But perhaps the manufacturers rate their breakers at 240 volts, and allow them to be used in either a 208 volt panel or a 240 volt panel. Can anyone address this question?
blupony96
Member
- Location
- Benld, IL USA
Thanks for the concerns, but..........
Thanks for the concerns, but..........
Everyone is right. I am NOT doing the installation. Thank you for the concerns.
I am responsible for "designing" the addition of a 208v receptacle for our server UPS and acquiring the materials. I have obviously stated my question too loosely.
I am looking at GE 120/240V 30A THHQB and THQB breakers. Are these the proper breakers that I should have the installer use?
Thanks for the concerns, but..........
Everyone is right. I am NOT doing the installation. Thank you for the concerns.
I am responsible for "designing" the addition of a 208v receptacle for our server UPS and acquiring the materials. I have obviously stated my question too loosely.
I am looking at GE 120/240V 30A THHQB and THQB breakers. Are these the proper breakers that I should have the installer use?
blupony96
Member
- Location
- Benld, IL USA
The UPS is rated at 4000W/5000VA with a 208V input bucking to 120V output. Thus, I am assuming, the available fault current for the device would be 5000VA / 208V = 24A. I then should increase that by 25% to determine the size of the breaker, giving me 30A, correct?
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
This is the situation. Molded case circuit breakers are listed with maximum voltages.
- Location
- Bremerton, Washington
Breakers are listed for their maximum voltage to ground. For example breakers for a 120/240 and 120/208 are the same. However a 120/240 delta is 208 to ground and must use a 240 volt rated breaker as a 120 volt breaker won't clear a 208 volt ground fault.
Take a look at 240.83 and 240.85
- Location
- Bremerton, Washington
We appreciate you asking for help. We don't allow DIYers and that's where the earlier concern was.
qcroanoke
Sometimes I don't know if I'm the boxer or the bag
- Location
- Roanoke, VA.
- Occupation
- Sorta retired........
they both are bolt-in. THQB is 10,000 AIC. THHQB is 22,000 AIC
If you can you need to look at the load center and see what breakers are listed for use in that panel.
blupony96
Member
- Location
- Benld, IL USA
Thank You!
Thank You!
I opened the NEC and read the articles you referenced. Thank you! We have determined that I can use a 120/240V breaker, but still haven't concluded if I should use a GE THHQB or THQB breaker. How do I determine which to use in my application?
Thank You!
I opened the NEC and read the articles you referenced. Thank you! We have determined that I can use a 120/240V breaker, but still haven't concluded if I should use a GE THHQB or THQB breaker. How do I determine which to use in my application?
blupony96
Member
- Location
- Benld, IL USA
THQB, THHQB and THQD are listed.
pjholguin
Senior Member
- Status