25 amp breaker????!
- Thread starter nift21
- Start date
- Status
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: 25 amp breaker????!
It could very well be a water heater with a 4500 w element. Or a motor load with 14 AWG conductor.
Or it what was on the truck.
It could very well be a water heater with a 4500 w element. Or a motor load with 14 AWG conductor.
Or it what was on the truck.
electricman2
Senior Member
- Location
- North Carolina
- Occupation
- Retired Electrical Contractor
Re: 25 amp breaker????!
Or some HVAC equipment where the nameplate specifies a 25A max OCPD.
Or some HVAC equipment where the nameplate specifies a 25A max OCPD.
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: 25 amp breaker????!
A 25A breaker would need a 10AWG conductor.
A 25A breaker would need a 10AWG conductor.
- Location
- Massachusetts
Re: 25 amp breaker????!
A 25 amp breaker does not necessarily need a 10 awg conductor.
HVAC equipment and motor loads come to mind.
A 25 amp breaker does not necessarily need a 10 awg conductor.
HVAC equipment and motor loads come to mind.
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: 25 amp breaker????!
Hi Bob,
This comes to mind for me;
Hi Bob,
This comes to mind for me;
I didn't notice any exceptions........
- Location
- Massachusetts
Re: 25 amp breaker????!
Dave it is right there in 240.4(D)
It is entirely code compliant to use a breakers in excess of the conductor ratings for motor loads and unit equipment.
Mike Holt has an example of 14 AWG on a 60 or 70 amp breaker feeding a motor load.
Dave it is right there in 240.4(D)
Take a look at table 240.4(G)
It is entirely code compliant to use a breakers in excess of the conductor ratings for motor loads and unit equipment.
Mike Holt has an example of 14 AWG on a 60 or 70 amp breaker feeding a motor load.
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: 25 amp breaker????!
Hi Bob,
I'd like to see MH's example where the branch circuit conductors are allowed to be protected like that. Where can I find it?
Now, if you were talking about control conductors, then I could understand!
Hi Bob,
I'd like to see MH's example where the branch circuit conductors are allowed to be protected like that. Where can I find it?
Now, if you were talking about control conductors, then I could understand!
- Location
- Massachusetts
Re: 25 amp breaker????!
Dave I looked around for it, we get a Mike Holt code tip each week with our checks, I saw it on one of those.
We have to remember that a breaker for motor loads is not for overload but short circuit and ground fault protection only, motor and conductor protection is from the motor overloads.
Another time 240.4(D) gets passed aside is in the tap rules.
Dave I looked around for it, we get a Mike Holt code tip each week with our checks, I saw it on one of those.
We have to remember that a breaker for motor loads is not for overload but short circuit and ground fault protection only, motor and conductor protection is from the motor overloads.
Another time 240.4(D) gets passed aside is in the tap rules.
speedypetey
Senior Member
- Location
- Hudson Valley, NY
Re: 25 amp breaker????!
I see 25's in a lot of these lovely modulars we have popping up like weeds around here.
Like has been said, mainly water heaters and equipment.
I see 25's in a lot of these lovely modulars we have popping up like weeds around here.
Like has been said, mainly water heaters and equipment.
- Location
- Illinois
- Occupation
- retired electrician
Re: 25 amp breaker????!
Dave,
A 1 hp 115 volt single phase motor has a full load current of 16 amps per Table 430.148. The motor branch circuit conductor must have an ampacity of 125% of the FLA per 430.22(A). 125% of 16 amps is 20 amps. A #14 TW has an ampacity of 20 amps per Table 310.16. 430.52 permits an inverse time breaker having a rating of 250% of the motor FLA to provide the branch circuit ground fault and short circuit protection. This would permit a 40 amp breaker to protect the #14 conductor.
Don
Dave,
A 1 hp 115 volt single phase motor has a full load current of 16 amps per Table 430.148. The motor branch circuit conductor must have an ampacity of 125% of the FLA per 430.22(A). 125% of 16 amps is 20 amps. A #14 TW has an ampacity of 20 amps per Table 310.16. 430.52 permits an inverse time breaker having a rating of 250% of the motor FLA to provide the branch circuit ground fault and short circuit protection. This would permit a 40 amp breaker to protect the #14 conductor.
Don
jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: 25 amp breaker????!
I took mikes course about 8 years ago. I remember something about #14 being protected at a very high #
No i would never do it
I took mikes course about 8 years ago. I remember something about #14 being protected at a very high #
No i would never do it
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: 25 amp breaker????!
Here's another way to look at it:
If you look at 240.5 (B) (1) it allows for a 18 AWG lamp cord to be used on a 20 amp circuit.
Of course this sounds excessive but there is two reasons why.
1. The Medium base socket in the lamp will limit the amount of current placed on the wire by the load. The same as the motor OVL's
2. If a short circuit were to occur in the lamp the resistance of this wire will still cause the OPCD to trip.
This is one reason I hesitate to install 20 amp circuits for general use receptacles. As I have seen some 20 awg tinsel cords on lamps from China that would not trip a 20 amp breaker. It would light up like a heating element.
Here's another way to look at it:
If you look at 240.5 (B) (1) it allows for a 18 AWG lamp cord to be used on a 20 amp circuit.
Of course this sounds excessive but there is two reasons why.
1. The Medium base socket in the lamp will limit the amount of current placed on the wire by the load. The same as the motor OVL's
2. If a short circuit were to occur in the lamp the resistance of this wire will still cause the OPCD to trip.
This is one reason I hesitate to install 20 amp circuits for general use receptacles. As I have seen some 20 awg tinsel cords on lamps from China that would not trip a 20 amp breaker. It would light up like a heating element.
- Location
- Massachusetts
Re: 25 amp breaker????!
You can not overload the 14s without the overloads tripping.
This is the same way we protect tap conductors, the overcurrent device is downstream from the conductors it protects.
If the wires short circuit or ground fault the 14s are more than enough to trip the breaker, in the same way we do not run full size ground conductors for circuits above 30 amps.
Jim why not, the conductors are protected by the motor overloads?
You can not overload the 14s without the overloads tripping.
This is the same way we protect tap conductors, the overcurrent device is downstream from the conductors it protects.
If the wires short circuit or ground fault the 14s are more than enough to trip the breaker, in the same way we do not run full size ground conductors for circuits above 30 amps.
A
a.wayne3@verizon.net
Guest
Re: 25 amp breaker????!
How about A/C compressors with a min ampacity of 15 amps. and a max breaker of 25 amps.You can still wire for min and fuse for max.(it`s legal as far as code) I personally would not wire it in 14 ga. but it is allowed
How about A/C compressors with a min ampacity of 15 amps. and a max breaker of 25 amps.You can still wire for min and fuse for max.(it`s legal as far as code) I personally would not wire it in 14 ga. but it is allowed
A
a.wayne3@verizon.net
Guest
Re: 25 amp breaker????!
It does seem like a sin but it`s not as long as the min ampacity is met(would I do it no)but it is allowed
It does seem like a sin but it`s not as long as the min ampacity is met(would I do it no)but it is allowed
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: 25 amp breaker????!
REmebmer for most applications the ampacity of 12 AWG THHN is 30. Only 240.4(D) limits it to 20 amperers after derating. Using a 14 THHN on a 50 Amp CB may not agree with you, but its OK per the code for a motor application.
REmebmer for most applications the ampacity of 12 AWG THHN is 30. Only 240.4(D) limits it to 20 amperers after derating. Using a 14 THHN on a 50 Amp CB may not agree with you, but its OK per the code for a motor application.
pierre
Senior Member
- Location
- Westchester County, New York
Re: 25 amp breaker????!
Nift
do you know what load the 25 amp breaker is feeding?
Just curious
Pierre
Nift
do you know what load the 25 amp breaker is feeding?
Just curious
Pierre
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