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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Here I found an old pic of the wire I used.

Overall diameter is approximately the same as in the chart you linked.

My 3 HP compressor draws 15A and this wire is rated at 20A ampacity.

Re: Aircon and Desktop PC in one circuit breaker

@Balarila
AWG12 rated at 9.3A? I think mas mahina ang insulation nito or 110V ang supply sa location nila.

Wire sizes and types has equivalent max. rated ampere. Since fixed yun supply voltage natin @ 220V ang nagbabago lang yun load natin. The higher the load (KW) the higher ampacity.

AWG#12(3.5mm2) THHN Wire, I think this is the minimum wire size you can used sa set-up mo considering non-continuous ang load mo.

You can go higher to AWG#10 (5.5mm2) THHN to be safe.

Re: Aircon and Desktop PC in one circuit breaker

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.

Because current rating is independent of wire length and resistivity, whereas a power dissipation rating is not, or would have to be expressed per unit length. Even if wire were to have a rated power loss per unit length, we would have to know the resistance per unit length, to back-compute the maximum current from P = I^2 R.

We usually think 'how much current can we pass through this wire' instead of 'how much power can we afford to lose'.

Re: Aircon and Desktop PC in one circuit breaker

In layman's term does it mean to have a "more than enough" cable and paired with an appropriate circuit breaker that could trip safely?

Re: Aircon and Desktop PC in one circuit breaker

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.

Please check the ampere rating of your stepdown first. Deceiving ang kW rating.

Re: Aircon and Desktop PC in one circuit breaker

We bought a new 0.75HP window-type aircon. Since we do not have a ready socket/outlet, I bought a socket with breaker (2 in 1) rated at 30A and asked the electrician to install. He tapped the new socket with breaker to our ordinary fuse box with 30A fuse and was able to test/run the aircon properly. Unfortunately, he noticed that the wiring installation of the house, although it is #12 stranded wire, he told us that it is sub-standard (not a Phelps Dodge wire). During nighttime, the only heavy load that we have is our 7 cu. Ft. refrigerator (145 watts indicated as “rated input” and 0.8A indicated as “rated current”). Now, he is unsure if the wire can handle the load with both the aircon and refrigerator running. Please help, thanks.

Re: Aircon and Desktop PC in one circuit breaker

test the actual ampere of the circuit using an ammeter at full load. then compare with the fuse/breaker.

Re: Aircon and Desktop PC in one circuit breaker

@bmac, thanks for your response. Unfortunately, we do not have an ammeter. Anyway, basing on computation/formula, my total amperage would yield to a total of 3.7 A (2.86 A+ 0.8 A), right? My concern is that, does my #12 wire could withstand the overnight use of both aircon and refrigerator? Thanks in advance.

Re: Aircon and Desktop PC in one circuit breaker

The #12 wire should be ok with that light load.

Re: Aircon and Desktop PC in one circuit breaker

thanks bigfoot2

Re: Aircon and Desktop PC in one circuit breaker

Did i get this right?
1. watts = voltage x amps
2. #12 stranded can be loaded with 25 - 30 amps. So conservatively, you can have 220 * 25 = 5500 watts (4400 with 20% margin)

@kabayan
not all electricians are honest. It might be that your wires are already old and need to be replaced. But some electricians just want you to replace the wire because they can sell your old wire as scrap copper. One good use for discarded old wire is for grounding. I use the old wire as the grounding wire for my 3 prong plugs. They don't normally carry current anyway, and they can protect your electronics.

Re: Aircon and Desktop PC in one circuit breaker

@bigfoot

I'm rewiring a flat in a 90's 4 storey building. The existing electricals don't provide a ground wire, but I'm on the top floor and in the kisame, the top of the the main foundation posts are visible, with rebars still protruding from the concrete. I'm assuming na baon yan sa lupa way below, will that be a good grounding wire? I can't use the pipes, they're all pvc.

Re: Aircon and Desktop PC in one circuit breaker

^I think the soil quality will also play a part on how good the grounding will be aside from how deep the rebars are buried into the ground. Not sure if an earth ground meter is locally used by some surveyors/contractors as it would help you identify your grounding problem.

Re: Aircon and Desktop PC in one circuit breaker

@jarod

I'm not entirely sure, but apparently rebars encased in concrete foundation act as an 'ufer' ground. Low impedance because of characteristics of the concrete. There's disagreement whether frequent high current grounds (lightning) damage the concrete, but i'm hoping that for low current purposes lilke ground fault interruption, it will be ok...