I am going to install wiring in my home and I am curious if I can use 16 mm or 2 core DC cable for AC small appliances like fans and TV?

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  • 3
    I'm voting to close this question as off-topic because it should be migrated to the DIY home improvement site. – Elliot Alderson Apr 18 at 19:18
  • 2
    Using non-code wiring is a great way to get your insurance claim denied when your house burns down – BB ON Apr 18 at 19:21
  • Given that this is a very sensible question and correct for diy.se, +1. Welcome to the home improvement stack exchange. – Harper Apr 18 at 22:03

If you do not know what cross-section or gauge of wire is appropriate for installation in a home or business, you should not be installing it, period.

There isn't a single "correct" type of wire to install, instead there are many factors which relate to:

  1. Local laws and building codes
  2. Amount of current drawn by the appliance(s)
  3. Number and type of outlets and total expected load on the circuit
  4. Type of breaker required (arc-fault, GFCI, etc.) (see #1)
  5. Inspection and testing (see #1, again)

You should contact an electrician to add or modify your residential wiring. If you insist on a do-it-yourself (DIY) approach, you should research your local electrical code and look for information on the above points. In order for that effort to be productive, you should first make sure you understand the following fundamentals:

  • voltage, current, and power
  • alternating vs direct current, polarity, neutral vs protective Earth/ground
  • wire cross-section/gauge; current capacity; resistance and voltage drop over distance; temperature derating; etc.
  • series and parallel circuits
  • electrical safety, circuit breakers/fuses, proper use of voltmeters (multimeter), etc.

As you can see there's a lot of basics that must be taken into account in order to answer your question:

  • How many amperes do your appliances draw? Do they require the same voltage? What sort of insulation is required based on fire code and voltage rating? (Your local laws dictate this.)
  • There's no such thing as a "DC cable."
  • What does "16mm" mean? If you mean 16 mm² (roughly equivalent to 5 AWG), that's a massive wire diameter for casual residential use, even for major appliances. (Some countries refer to wire diameter as 'cross sectional area', usually in square millimeters (mm²). Others use wire gauge, also known as American Wire Gauge (AWG). The superscript '2' is important.)
  • I presume you don't mean a wire length of 16mm, as that's impractically short for any appliance purpose.
  • Most wiring is sold as having a number of conductors, not cores; and for most residential and commercial wiring, three or more conductors are used (e.g. line, neutral, and protective earth/ground). Therefore, two is likely not appropriate... Unless you're talking about a replacement cord for a small appliance or fan, where such devices often have only a two-conductor power cord. This, however, would not be considered "installing wiring in your home". Instead it would be more of an "appliance repair" or a "replacement of power cord." If so, this is a more reasonable DIY project, which your local hardware store can assist with.
  • I am suspicious you may be meaning a two-conductor 16 gauge (not mm) cable to replace, for example, the power cord on a fan. If so, you should be able to inspect the damaged power cord and replace it with the same (or thicker) gauge. Again, your hardware store can assist. They also will have replacement plugs in case you only need to replace the plug and not the entire cable. If you need to open the appliance/device to attach the new cord, you may encounter other problems. For example, if you are not familiar with soldering or crimp terminals on wires, etc.

This can be a culture shock for electronics guys used to wiring stuff wing-ding with a wall-wart and a breadboard. Mains wiring is regulated. The regulations are additive - they list what you can do, with all else forbidden.

Most countries follow the USA NEC, or analogous rulebooks which brazenly steal from each other. NEC is published by the National Fire Protection Association, a trade group supported by insurance companies. The major US safety testing lab is Underwriter's Laboratories (UL), and "Underwriter" is another word for "insurance company".

Must be [UL] listed as equipment

For instance, when I search 16mm 2-core cable, all the top hits are Alibaba. You can't use anything from Alibaba. Since legality is inclusive, what's more accurate is all equipment must be approved, i.e. UL listed or by competing NRTLs such as CSA, ETL etc. CE is not a testing lab.

By "equipment" I mean finished-goods products ready to install in mains wiring. The difference can be subtle. For instance, if your dimmer is making your LED lights glow, and you want to add a capacitor/resistor to allow it some bypass current, you can use this one because it is equipment with a UL listing. You a cannot use a component out of an electronics catalog with a ЯU listing.

Wiring methods decide wire type

NEC Article 300 lists the various wiring methods that are allowed, and the wires or cables that can be used with them. For instance Article 334 describes the wiring using the NM wiring method (aka Romex). Article 340 covers the wiring done with outdoor UF cable.

An important part of any cable design is physical protection from other construction and the environment at large (heat, wet, physical damage etc.)

Article 342-392 cover various forms of conduit or other raceway. Then, Article 310 talks about what types of wire can go in those conduits/raceways. The raceway is responsible for some environmental protection (mainly physical) but the wire itself must contend with other environmental threats (heat, wet for instance).

Other chapters cover cordage, which is flexible cord intended for interconnect of plug-in appliances or lighting. You know what cordage is; you handle it all the time. Cordage such as SJOOW is never allowed to be used in walls or conduit or raceway.

All wires must be marked with the various certifications it has. Unmarked wire is not legal for use, which is why you cannot shuck the sheath off cables and use the wires within.

If your wire is bona-fide UL listed (or equivalent NRTL), and the wires or cable sheath are marked as a correct type (such as NM-B or THWN-2), and it is sufficient size for the task, then it is acceptable as wiring. Otherwise, no.

It's entirely possible you could find some 2-core 10mm DC cable that has "UF-B 600V" rating right on it, in which case, you're all set. I wouldn't count on that; I'd go down to my friendly neighborhood electrical supply house and use the wire or cable that is legal and customary for the work you are doing. Wire, particularly building wire, costs very little.

Also, at the 10mm2/16mm2 size, you should really be considering AA-8000 alloy aluminum for fixed installations, with appropriate size bump to account for the reduced ampacity-per-volume of Al.

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