Re: Aircon and Desktop PC in one circuit breaker

You need at least a 60amp main breaker with branches for your house extension. A #8 wire is adequate. From this main breaker separate the CO, Lights, AC, Ref. Increasing the rating of your breaker from 30 to 40 amps will not help, better trip the breakers than overheat the cables. just my 2 mameras.

Re: Aircon and Desktop PC in one circuit breaker

Thank you very much for that reply! My electrician fixed it already, there was indeed a loose connection with one of the sub-CB so i bought a new 30 amps of CB and so far when I plug in my desktop, it doesn't flicker just like before.

Re: Aircon and Desktop PC in one circuit breaker

Agree that you shouldn't change a breaker, because the wire will be suited to the breaker. 40 amp circuit breaker on 12 gauge wire will result in an overload, perhaps leading to a fire.

Re: Aircon and Desktop PC in one circuit breaker

I hired an electrician to inspect my house. He checked my circuit breakers.
I have 40 amps, 20 amps and 30 ams. But what startled him and myself, he told me, the electrician who did my house, used 12 gauge wire for all circuit breakers.

He told me, the 12 gauge wire is good for 20 amps but not for 40amps. This concerned me.

My wires are by phelp dodge.

Question:
A). Can I exist with my 12 gauge wire for my 40 amps circuit breaker dedicated to an aircon. The aircon is 1 hp.

Thanks

It's too costly to have it replaced.

Re: Aircon and Desktop PC in one circuit breaker

Your 1hp will draw 3.4 amps (=745/220), more during startup but this is normally momentary. Of most concern is always the continuous running current since this is what will cause the wire to heat up. Gauge 12 wire is specified to take 9.3 amps in closed conduit or bundle so you are still safe. At the plant, I used to put my hand to wires to check if we were running them safely.

Getting back, even though you know that the wire in your house can take the 1hp load, I strongly recommend that you change your breakers to suit the actual wire size. Unless your wires are not buried in conduits this is your only recourse with the installed wiring. Remember, breakers are meant to protect the wire and in turn your house from burning down.

You'll have less load capacity but you can redistribute your loads. Most household circuits do not really need the full capacity of a branch (unless you insist on connecting a welding machine as I did :)). If you need more current then just put in a new circuit with wire that is rated for your loads.

Re: Aircon and Desktop PC in one circuit breaker

Some unknowing electricians may use a 40 amp breaker, but connect two separate branches to it, each with 12 gauge wire. But this is not advisable, as the breaker will not trip if one of the branches draws more than 20 amps. EAch breaker should be rated for the size of wire, as lncc states.

Re: Aircon and Desktop PC in one circuit breaker

first, check your load per circuit.

then replace the 40A with 20A, add circuit if possible.by doing so, you will satisfy yourself with what you have at the moment.

Re: Aircon and Desktop PC in one circuit breaker

May as well piggy back on this thread (conservation!).

I have a 5kW stepdown (thanks, Timber) which I plan to plug into my shop's power socket (circuit breakered at 20A) then, on the load side, I plan to hang a conduit on the ceiling (sort of like an electrical manifold) from which will hang sockets that will deliver 110V for my US bought power tools. Those sockets will be for round-prongs and I will put round prongs on all my 110V power tools.

But let me get to the questions:

1. What wire gauge should I use? I saw in a message above that AWG12 is rated at 9.3A. That would be about 2KW capacity, right? I probably will never load the stepdown up to 5kW but I'd rather make the wires maxed out then constrict a bit on the circuit breaker. A quick google led me to a table that seems to indicate I should get AWG9. Would this be right?

2. What kind of wires should I use? I can use THN wires for the part that would be inside the conduit. But for the part that would hang from the ceiling, I would think I need some thickly insulated wire. Where could I source these?

3. Where can I get some 20A rated sockets that would hang from the power cables?

4. Is there a special way of connecting these wires in the junction boxes? I was thinking of getting one of those bright colored plastic covered twist-connect thingies.

Thanks for any help. I'm pretty handy around the house but my electrical knowledge is mostly theoretical, enriched by watching electricians who may or may not know what they're doing.

Re: Aircon and Desktop PC in one circuit breaker

@ Balarila

1. Since 5KW ang max load transformer mo, then 220V ang supply mo.

5000/220 = 22.7Ampere

You can use 3.5mm2 or #12 stranded na THHN (phelp dodge) wire rated @30A.
or 5.0mm2 #10 stranded TW or TWN wire rated @30A. Mas mahina kse insulation ng TW at TWN wire compare sa THHN. Then you can use 30A circuit breaker.

Re: Aircon and Desktop PC in one circuit breaker

@ Balarila

1. Since 5KW ang max load transformer mo, then 220V ang supply mo.

5000/220 = 22.7Ampere

You can use 3.5mm2 or #12 stranded na THHN (phelp dodge) wire rated @30A.
or 5.0mm2 #10 stranded TW or TWN wire rated @30A. Mas mahina kse insulation ng TW at TWN wire compare sa THHN. Then you can use 30A circuit breaker.

Thanks, Bryant77. I can see why you recommended 30A rated wires.

I am presently considering a 20A max system because:

- Normally, when one gets a transformer, one allots some headroom, so I foresee, I will never push mine beyond 4kW or, conservatively, 20A.

- I can't find fitings beyond 20A; 15A is hard enough.

Does my train of thought make sense or do practical applications make my approach nonsesical?

Re: Aircon and Desktop PC in one circuit breaker

If it helps I note that all my power tools wiring are in AWG # 12 stranded be it 110V or 220V. I use Phelps Dodge cables. I have not encountered any problems.

The 3 HP compressor I have ( 15A ) also use AWG #12 but on it's own dedicated circuit.

Most probably my power tools will run on a smaller wire but at AWG 12 I still have some room for future upgrades ... i.e. the need to run several power tools simultaneously.

Re: Aircon and Desktop PC in one circuit breaker

Thanks, JayL.

Pardon me for being thick about this. But, from some googling (and BBN's message above), I noted that AWG12 is rated at 9.3A. But frmo Bryant77's message, he mentions a Phelps Dodge #12 rated at 30A. You also have no problem using AWG12 Phelps Dodge.

Do I understand correctly then that, Phelps Dodge probably uses some special conductor that allows higher current capacity in relatively thin cables?

I am also confused why wires are rated in Amperes. I would have thought power rating is more relevant since it is indicative of possible heat generation/tolerance.

Re: Aircon and Desktop PC in one circuit breaker

This is the wire I use. Phelps Dodge. I already threw away the carton but I remember seeing THN or something written on the box. I'm using this only for the distribution wiring in my shop which are not very long probably max out at 10 m per run. I checked the line coming from the breaker box ( from where I tap ) and seems like the wires are thicker.

Approximate overall wire diameter ( excluding insulator cover ).

Please take my setup with a grain of salt as I have really not done the exercise to do full computations when I did this. But I've had it for more than 2 years now and it works for me. Normal power tools use. The biggest I have are the compressors 3 hp and 2 hp using this wire size. The 2 HP share the same line with 2 bench grinders while the 3 HP has a dedicated line. Breakers are 20A and 30A respectively.

My distribution lines are external .... the garage is old now and was not wired to be a shop. If only I knew better when I had it constructed then I would have done all these provisions built in ... well maybe next time.

Re: Aircon and Desktop PC in one circuit breaker

Copy.

Checked out the Phelps Dodge webpage: http://www.phelpsdodge.com.ph/Word%20Documents/THHN.pdf
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