Finding how many amps a circuit breaker can take maximum

pcslookout

Lifer
Mar 18, 2007
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156
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Is there anyway to tell how many amps a circuit breaker can take maximum without having to keep on breaking fuses ? I don't break fuses on purpose to tell.

I am trying to figure out if 5 computers on and a projector all on the same circuit breaker will have enough amps without breaking a fuse.

 

natto fire

Diamond Member
Jan 4, 2000
7,117
10
76
?
Does your panel use circuit breakers or fuses?
These are different types of overload protection devices.

EDIT: Going to assume you live in a newer dwelling with GFCI circuit breakers. Tripping these does not damage them, so the best way to find out is to load up the circuit and pray some n00b electrician did not use a higher breaker than the wire can handle. (Most home circuits are 15A, which I believe is about the max for 12 AWG wire)
 

spidey07

No Lifer
Aug 4, 2000
65,469
5
76
Look at the breaker or fuse. That will tell you.

Doubtfull you'd blow a regular 15 amp circuit with just that stuff.
 

pcslookout

Lifer
Mar 18, 2007
11,959
156
106
Originally posted by: spidey07
Look at the breaker or fuse. That will tell you.

Doubtfull you'd blow a regular 15 amp circuit with just that stuff.

Well it has happen when 3 computers were on all at the same time. Then when the laser printer was turned on the fuse blew.

What does this mean ? A laser printer takes up the most amps ?

 

natto fire

Diamond Member
Jan 4, 2000
7,117
10
76
Originally posted by: pcslookout
Originally posted by: spidey07
Look at the breaker or fuse. That will tell you.

Doubtfull you'd blow a regular 15 amp circuit with just that stuff.

Well it has happen when 3 computers were on all at the same time. Then when the laser printer was turned on the fuse blew.

What does this mean ? A laser printer takes up the most amps ?

Laser printers do draw quite a few amps when "warming up".

Does anything else in the house go off when "the fuse blows". (again, I think you might be referring to a tripped circuit breaker)
It is common practice, especially in older homes, to share 1 circuit for many outlets.
 

BigJ

Lifer
Nov 18, 2001
21,330
1
81
Your laser printer when it turns on is pulling a lot of juice (drawing more power when starting up than when actually operating). This is causing the breaker to trip or the fuse to blow.
 

SuperNaruto

Senior member
Aug 24, 2006
997
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Printer when starting up uses more than idle amperage.. some printer uses 15 amps to start up and 8 amps idle..

most circuit are rated for 15 amps.. so adding a printer, will just blow the circuit
 

BigJ

Lifer
Nov 18, 2001
21,330
1
81
Originally posted by: Captain Howdy
?
Does your panel use circuit breakers or fuses?
These are different types of overload protection devices.

EDIT: Going to assume you live in a newer dwelling with GFCI circuit breakers. Tripping these does not damage them, so the best way to find out is to load up the circuit and pray some n00b electrician did not use a higher breaker than the wire can handle. (Most home circuits are 15A, which I believe is about the max for 12 AWG wire)

12ga wire is rated for 20A lines. 14ga is the minimum required for 15A stuff, except in certain circumstances.
 

pcslookout

Lifer
Mar 18, 2007
11,959
156
106
Originally posted by: SuperNaruto
Printer when starting up uses more than idle amperage.. some printer uses 15 amps to start up and 8 amps idle..

most circuit are rated for 15 amps.. so adding a printer, will just blow the circuit

What about computers ? How many amps do the average pcs take each and what about a projector?
 

BigJ

Lifer
Nov 18, 2001
21,330
1
81
Originally posted by: pcslookout
Originally posted by: SuperNaruto
Printer when starting up uses more than idle amperage.. some printer uses 15 amps to start up and 8 amps idle..

most circuit are rated for 15 amps.. so adding a printer, will just blow the circuit

What about computers ? How many amps do the average pcs take each and what about a projector?

Buy a Kill A Watt device and you can measure the draw on each PC. The power consumption of computers will vary over the years.
 

pcslookout

Lifer
Mar 18, 2007
11,959
156
106
Originally posted by: BigJ
Originally posted by: pcslookout
Originally posted by: SuperNaruto
Printer when starting up uses more than idle amperage.. some printer uses 15 amps to start up and 8 amps idle..

most circuit are rated for 15 amps.. so adding a printer, will just blow the circuit

What about computers ? How many amps do the average pcs take each and what about a projector?

Buy a Kill A Watt device and you can measure the draw on each PC. The power consumption of computers will vary over the years.

Ok. Do you know if pcs or projectors take more amps when first booting up like laser printers do ?
 

natto fire

Diamond Member
Jan 4, 2000
7,117
10
76
Originally posted by: pcslookout
Originally posted by: BigJ
Originally posted by: pcslookout
Originally posted by: SuperNaruto
Printer when starting up uses more than idle amperage.. some printer uses 15 amps to start up and 8 amps idle..

most circuit are rated for 15 amps.. so adding a printer, will just blow the circuit

What about computers ? How many amps do the average pcs take each and what about a projector?

Buy a Kill A Watt device and you can measure the draw on each PC. The power consumption of computers will vary over the years.

Ok. Do you know if pcs or projectors take more amps when first booting up like laser printers do ?

Yes, they do, but not near the magnitude of difference of a laser printer. In fact some would say the higher current draw of a PC at startup is negligible, but it depends on the system in question, HDDs, especially. Thanks for the correction BigJ, this is all from memory and I couldn't remember for sure. Hence the weasel word "I believe", a rare courtesy on these forums. (Everyone is an expert here, lol)
 

pcslookout

Lifer
Mar 18, 2007
11,959
156
106
Originally posted by: FoBoT
they have a rating printed on them , go with that


good luck on your housefire


lol I wouldn't mind a fire. Would be quite exciting to save everyone!
 

pcslookout

Lifer
Mar 18, 2007
11,959
156
106
Wow I didn't think my projector took so little amps! Only 1.8 Amps max. That seems low. Did I do something wrong when converting the number?
 

pcslookout

Lifer
Mar 18, 2007
11,959
156
106
1.8 Amps maximum seems like so little for a projector. I thought projectors used a lot of Amps ?

Do normal printers use a lot of Amps when starting up and then going to idle? What about fax machines?
 

Linflas

Lifer
Jan 30, 2001
15,395
78
91
I'm pretty sure the breakers in my house have the number embossed on the switch end.
 

hanoverphist

Diamond Member
Dec 7, 2006
9,867
23
76
Originally posted by: Captain Howdy
Originally posted by: pcslookout
Originally posted by: spidey07
Look at the breaker or fuse. That will tell you.

Doubtfull you'd blow a regular 15 amp circuit with just that stuff.

Well it has happen when 3 computers were on all at the same time. Then when the laser printer was turned on the fuse blew.

What does this mean ? A laser printer takes up the most amps ?

Laser printers do draw quite a few amps when "warming up".

Does anything else in the house go off when "the fuse blows". (again, I think you might be referring to a tripped circuit breaker)
It is common practice, especially in older homes, to share 1 circuit for many outlets.

its common practice in new homes as well.

every device you can plug in has a listing for input and output power. look at the tag, find all the max output amps and add them up. if you have more than 15 (standard house circuit breaker) then youre running too hot. if its a gfi circuit, look into the fact that the outlet gfi is borked. if youre way under, check your circuit breaker at the power box to verify its not drawing too much by itself. those wear out, they arent forever.

as for what does the stuff draw? if you have a 1500W microwave hooked up to a wall outlet, youre going to have a 12.5A draw. for a 15A outlet, youre going to be right at the top of that, and most anything you plug in will trip it. divide the watts by the voltage and you can start counting up your devices on that line. most of this stuff is from my head, the calc was from one of my engineers, just asked him how many amps a 1500W microwave draws from a 15A outlet in your kitchen.

most of the stuff i have to gauge is listed with its FLA value, so i dont calc those much at all.
 

hanoverphist

Diamond Member
Dec 7, 2006
9,867
23
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Originally posted by: pcslookout
Originally posted by: SuperNaruto
Printer when starting up uses more than idle amperage.. some printer uses 15 amps to start up and 8 amps idle..

most circuit are rated for 15 amps.. so adding a printer, will just blow the circuit

What about computers ? How many amps do the average pcs take each and what about a projector?

500 power supply draws 3A

i have 21 puters on a dedicated circuit, 15A outlets and have no issues. these systems have CPU and monitors powered. some even have speakers and other peripherals plugged in, despite me telling them not to plug crap into the orange plugs. i also have 3 heavy duty laser printers (canon 2200, konica bizware 500 and another konica 9000) on the same outlet circuit with no issues at all. of course, we built this room and wired it ourselves, and we are an industrial electrical contractor. the guys knew what they were doing, and set it up the right way.