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#7734 02/20/02 09:01 AM
Joined: Jan 2001
Posts: 5
B
Junior Member
I have a friend who was asking me about a problem he is having in his house. He keeps tripping 10 amp circuit breakers, especially on the freezer and micro wave circuit. First, I didn't know it was acceptable, especially in a newer home, to use 10 amp breakers. I cannot find in the code where it states that you can and what wire size to use. Is this acceptable, or should the breakers be changed, if the wire size is correct?

#7735 02/20/02 11:51 AM
Joined: Feb 2002
Posts: 840
C
Member
10 amp breakers? [Linked Image] That's a new one on me!! Could you give us some more information? Like the manufacturer and model # of the breakers and panel?

Are you sure that the writing hasnt worn off on the breaker and you are misreading it?


Peter
#7736 02/20/02 12:00 PM
Joined: Mar 2001
Posts: 2,056
R
Member
I believe some manufacturers make "unit breakers" to be individually mounted on a din rail or similar application, to protect specific piece of equipment. However, for branch ckts., 210.3 shows a minimum rating of 15 amps. Also, I don't believe UL lists branch circuit breakers below 15 amps

[This message has been edited by Redsy (edited 02-20-2002).]

#7737 02/20/02 12:50 PM
Joined: May 2001
Posts: 176
W
Member
You are right Redsy. Square D makes a QOU unit mount miniature breaker as low as 10 amps in 120/240 volts 1,2,3poles and 277 volts 1pole.
Art. 240-6 of the 1999 NEC list only as low as 15 amps, but the next sentence says non-standard fuses and inverse time breakers shall be permitted.

#7738 02/20/02 12:50 PM
Joined: Nov 2000
Posts: 2,236
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Square D and other breakers have a large #10 on the face, which means 10,000 Amps Interrupting Current, not 10A Overcurrent protection.

Look closer at the black numbers on the toggle itself if Sq D, or near there...

It should say either 15, 20, (or God forbid) 30 on it...


-Virgil
Residential/Commercial Inspector
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#7739 02/20/02 02:09 PM
Joined: Jan 2001
Posts: 5
B
Junior Member
Thank you guys for your quick response to my inquiry. I have sent these responses to my friend who is going to double check his panel tonight. I am hoping it is what sparky66wv suggested. Will keep everyone posted.

#7740 02/21/02 08:51 AM
Joined: Jan 2001
Posts: 5
B
Junior Member
After further investigation, he discovered it was a 15 amp circuit breaker, with the large #10 on it. Well, he still has a problem, but I feel better. Thank you guys for your help.

#7741 02/21/02 08:53 AM
Joined: Jul 2001
Posts: 599
J
JBD Offline
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10 amp breakers are common in industrial control panels. Square D makes a QO plug-on and QOB bolt-on panel style in 1, 2, and 3 pole versions as well as their unit mount QOU. (Look at page 8-10 in their Digest).

These are not common in normal panels or loadcenters.

#7742 02/21/02 10:20 AM
Joined: Oct 2000
Posts: 4,081
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Bob,

Does He have a Microwave over the Stove?
Just a guess, because Kitchen receptacles should be on 20A circits. A common situation I've seen is for someone to replace a range hood (which is on a 15A general purpose circuit with multiple other loads) with a Microwave unit. It should have been put on a dedicated circuit.

Bill


Bill
#7743 02/21/02 10:21 AM
Joined: Feb 2002
Posts: 840
C
Member
Bob-
Youre Welcome. [Linked Image] I suggest having an elctrician come take a look at that situation. It is possible that the #10 does not run throughout the entire ciruit, which would make it dangerous to upgrade the breaker to a 20 amp or 30 amp. Someone could have tapped #12 or #14 off of it, seeing that #10 is cumbersome to work with. At any rate, I would suggest professional assistance.


Peter
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