AC Cable vs DC Cable?

Don't get involved.

Don't hook it up backwards.

You mean like hooking up the A/C power as C/A or the D/C power as C/D?

Weeeellllllllll,

AC current travels one way, then reverses itself and goes the other. (Alternating, as it were) During the time when the little electrons are stopped and turning around, the wire has time to rest.

With DC current, it's always going the same direction, so the wire gets no rest.

That's why if the wire is hooked up backwards the electrons will be confused and bump into each other causing overheating and loss.

A simple test will indicate which way current flows in a DC wire.

I hope this helps.

I would try it. Since solar works with low voltage the only difference is the amperage for the same power.

no precautions needed other than a topped up live insurance

Do you think that the impact of DC current is same as AC current of equal rating?

Fundamentally both are different, right?

I think we need to rate DC current 50% lesser than AC current? (though there is no theoretical proof)

You are way over your head. Think again a change in Voltage and amperage has a profound effect on the cable. Even when the power is the same it will have to be different. Use the specified cables.and don't be cheap.

alternative buy a good house insurance additionally.to.the live insurance. You will need it.

You appear to be the first who understands that reading from the top down here.....well done!!!

I would guess that NO EEs have posted up till you did.....

You deserve a GA as well.....for being the first!!

No. Solar doesn't work with low voltage. Typical residential systems involve voltages that can near 600 volts. And being DC makes it all the more dangerous.

Cable that is solar rated is typically high voltage, sunlight & UV resistant as well as weather resistant.

If you are that concerned that "regular 1.5 sq mm cable" may not be acceptable then don't use it. Why take the risk if you're not sure?

12kW is a decent amount of power, and 1,100V is way beyond dangerous/lethal. If you're trying to save money by not buying the cables that come as part of the PV system then you are making a big, and potentially costly, mistake.

Those cables are fitted with factory prepared connectors and insulation systems that can handle the combination of voltage, current, and environmental conditions that exist above your roof. You will find that the money you think you're saving will be lost the first time you have to go up and repair the damage caused by a poorly mage up connection that overheats, arcs over, and sets your roof on fire.

I'm assuming you know the below differences:

AC wire experiences REACTANCE (XL, XL) and IMPEDANCE (Z).

DC wire experiences RESISTANCE (R).

1. There is no such thing as "regular cable". There are many different types of cable, designed for various applications and environments. For instance, if you are placing cable inside conduit in a ground floor slab, the cable must be approved for wet locations, even though it is in conduit.

2. Cable is not sized based on power. Cable is sized based on two factors. 1. The jacket insulation must be rated for the highest voltage likely to touch either the inside or outside. 2. The conductors must be of sufficient gauge to carry the expected amperage.

There are special solar cables available in market

Yes but for different reasons (not because they are carrying DC instead of AC). Think UV protection, resistance to ice, fitted with special connectors to make connection easier and safer, etc (because they are potentially exposed to the elements when laid on the roof).

What exactly are you trying to do as low voltage DC can kill just as easily as AC?

• There are special solar cables available in market. Can a regular 1.5 sq mm cable rated 1100V , 11A be able to carry the equivalent DC power?

Current is current. DC tends to travel through the whole cross sectional area of a wire, AC tends to move toward the surface (skin effect), but if the conductor is made up of multiple strands of smaller diameter wire, they share the load very equally. So when a wire is given a current rating, that is generally done with AC, because technically the same wire could probably handle more current with DC. But nobody states that, the current rating is always the worst case scenario, which leaves some additional margin of error. So if you have wire rated for 11A, that means 11A AC as the worse case scenario, it is absolutely fine with 11A DC.

The VOLTAGE rating of a wire has only to do with the insulation, and what is called the "partial discharge" capability of the insulation. In an AC cable, there is a tendency for the cables to start acting like a capacitor and a charge builds up on the outer surface, trying to discharge into other nearby cables when their sine waves are at lower potentials, or to ground. None of that is an issue for DC, so again, the voltage rating expressed on a cable is usually AC RMS voltage, which by the way means the real PEAK voltage will be roughly 40% higher. So again, if it is 1100V AC rated, it's fine for 1100VDC. It's also by the way highly unlikely you have 1100VDC coming from a solar panel. Some large commercial / utility sized solar farms use 1000VDC now, but that would be fine.

So as mentioned previously, the special nature of "solar" cables has to do with OTHER physical properties inherent in solar panel installations, not often associated with field wiring of AC systems.

• What will be the restrictions or precautions?

The issues will come with the terminations and devices connected TO the cables, not the cable itself.

Actually there is a difference between how AC and DC utilise the conductors axial surface area, its called the "skin effect" at 60 Hz most of the current is flowing at a depth of 8mm below the surface, while DC utilises the whole area. Of course in this case the difference between the two is virtually zero. By the way at 1 MHz the skin depth is 0.07 mm.

It has been proposed to transmit our power via DC in order to reduce loss of energy.

With modern solid state components it might be possible?

Flowing 8mm below the surface is a cute trick in wire of 1.5 mm² cross-section._^.

I'd like an explanation.

I'd pick up the phone and ring a qualified Electrician to size and select the cable, Mildred. Then, I'm funny that way.

Simply apply the correct national electrical standard; in the UK it is BS7671.

It must be April fools.

The "usual" cable according to UL 83 or UL 44 is different with respect to solar cable

fabricated according UL 4703.

Theoretical an a.c. cable could be ok for d.c. supply system and for a while [not permanently]

you may use it. See:

https://www.anixter.com/content/dam/anixter/resources/techbriefs/anixter-summary-of-photovoltaic-wire-requirements-as-outlined-in-ul-4703-techbriefs-en.pdf

There is no difference in the cables. The only difference is the type of electrical power being transmitted. AC or DC applications use the same wires.

You should pick up gardening. Your knowledge is rather limited similar to mine but at least I understand that cable even tough they are all wire and isolation are not the same.

The difference has been pointed out as in isolation strength and cable size to match Voltage and Amperage. So one has to look at what Voltage and Amperage the cable has to convey. Nothing of which has been specified and it is highly doubtful that the solar system has the same rating as the cable.