I am renovating and intend fitting both 12VDC and 230VAC lights in various rooms.  It has been pointed out a number of times here that AC and DC circuits are not allowed in the same conduit.  So I will chase the walls open to fit a 2nd conduit.  🙄

My question is this:  Is it allowable to run DC & AC into the same 2x4" wallbox and fit two switches on one bezel, one for AC and one for DC?   Or do I need to fit two wallboxes, one for AC and one for DC?

Out of interest, why are you fitting both ac and dc in tla room? 

54 minutes ago, Superfly said:

seems the regs merely need Galvanic isolation (which a transformer provides) ... so a wall box with a transformer should satisfy that - dunno if one gets wall boxes that will house it with the switch anyway 

Transformers in wallboxes?  No you misunderstood me.  I want to implement a 12VDC bus or distribution network that gets fed from a battery charger/battery.  In addition to the existing 230VAC lights wiring, I want to add further 12V lights.  I would prefer to operated all lights (AC & DC) from one common switch bezel if that is legal.  I wanted to run the 12VDC cables down the same conduits as the current mains wires.  However, SANS stipulates that AC and DC wires may not run in the same conduit or trunk.  So I say, OK, I will provide a separate DC conduit.  The question is, is it legal to run DC and AC into one wallbox.  I presume it is NOT.  From a legal point, the wall-box can be seen as an extension to a conduit or trunk, and will likely be subject to the same rule.  A STUPID rule!

Electrically speaking there is absolutely nothing wrong with running DC & AC wires in close proximity.  Just about all major appliances such as washing machines, electronically controlled fridges, microwaves, etc.  have AC/DC wires bundled in long harnesses.

So the SANS issue has nothing to do with underlying electrical engineering issues, but rather some soft issue of what I regard as over-bearing governance to protect an idiot from poking around in wiring and possibly getting confused.  I think the problem comes in with SANS not differentiating between low voltage and high voltage.  (They user the same words with totally different meaning to what I regard as LV & HV).  I agree that high DC voltages are potentially more lethal and that HV DC should thus be handled differently.  But 12VDC is inherently safe.

@Dimi  I dislike centralized systems.  Normally people have one inverter and all the lights are on the essential circuit.  If that inverter fails the whole house is in darkness.  I know one can use battery-backed up LED bulbs, etc.  But I don't like it.  The most critical lights are in the staircase and those lights are small.  There are no battery-back-up options for that.  There are some other reasons as well, but I have mentioned them in various other dialogs.

16 minutes ago, Modina said:

Transformers in wallboxes?  No you misunderstood me.  I want to implement a 12VDC bus or distribution network that gets fed from a battery charger/battery.  In addition to the existing 230VAC lights wiring, I want to add further 12V lights.  I would prefer to operated all lights (AC & DC) from one common switch bezel if that is legal.  I wanted to run the 12VDC cables down the same conduits as the current mains wires.  However, SANS stipulates that AC and DC wires may not run in the same conduit or trunk.  So I say, OK, I will provide a separate DC conduit.  The question is, is it legal to run DC and AC into one wallbox.  I presume it is NOT.  From a legal point, the wall-box can be seen as an extension to a conduit or trunk, and will likely be subject to the same rule.  A STUPID rule!

Electrically speaking there is absolutely nothing wrong with running DC & AC wires in close proximity.  Just about all major appliances such as washing machines, electronically controlled fridges, microwaves, etc.  have AC/DC wires bundled in long harnesses.

So the SANS issue has nothing to do with underlying electrical engineering issues, but rather some soft issue of what I regard as over-bearing governance to protect an idiot from poking around in wiring and possibly getting confused.  I think the problem comes in with SANS not differentiating between low voltage and high voltage.  (They user the same words with totally different meaning to what I regard as LV & HV).  I agree that high DC voltages are potentially more lethal and that HV DC should thus be handled differently.  But 12VDC is inherently safe.

@Dimi  I dislike centralized systems.  Normally people have one inverter and all the lights are on the essential circuit.  If that inverter fails the whole house is in darkness.  I know one can use battery-backed up LED bulbs, etc.  But I don't like it.  The most critical lights are in the staircase and those lights are small.  There are no battery-back-up options for that.  There are some other reasons as well, but I have mentioned them in various other dialogs.

1.   If there is LS when the inverter fails you would have been in a whole house of darkness in any case. 

2.   To prevent this for longer than 3 minutes when there is no LS you just flip your transfer switch. 

@Modina the reason I was asking is because I'm trying to put together a really low cost but effective solution to lighting.

Please check out this thread, I'd love to hear your thoughts. 

 

15 minutes ago, Dimi said:

@Modina the reason I was asking is because I'm trying to put together a really low cost but effective solution to lighting.

Please check out this thread, I'd love to hear your thoughts. 

 

Nothing against the 6x18650 but if they are new cells and you have to add the mini inverter the cost does rise. 

Whaf can also work but is very obvious is a ceiling fan pull switch to switch some LED down lights. You then run the whole house from 1 battery of 12V directly. 1 charger for this battery. One can add a day/nite switch on the battery positive so no energy is wasted during day time. This is what I have done in 2005. I just used 1 or 2 x 1W LEDs per room. Still happy with it. This gives me light to transfer my inverter to drive the normal lights. Some evenings after supper and relaxing there is sometimes not even a need for normal lights. 

1 light in kitchen and garage is unswitched but through the day nite switch. These 2 are always on during the night. 

I use a 315MHz wireless 16 relay controller to switch on or off all my 12V DC lights. No need to run more wires than I need too.

This I installed years ago, and to be honest since the inverter was installed, I have never used them again. 👍

As for the separation of AC / DC wires, maybe sprague can be used to technically separate the wires in the conduit and wall-boxes?

You can use a divider inside trunking to legally separate the dc and ac wires but can you do it in a wallbox?

54 minutes ago, Vaal said:

You can use a divider inside trunking to legally separate the dc and ac wires but can you do it in a wallbox?

Yes I am aware of a divider inside trunking being allowed to separate AC and DC.  A divider in a 2x4" wallbox is not workable.  In a 4x4" maybe.  I might need to use two wallboxes or otherwise switch all lights to 12V operation.

On 2023/05/21 at 11:18 AM, Modina said:

  I agree that high DC voltages are potentially more lethal and that HV DC should thus be handled differently.  But 12VDC is inherently safe.

I tend to agree with your statement to me power conductors of AC and DC systems rated 600V or less can occupy the same raceway, cable, or enclosure if all conductors have an insulation voltage rating not less than the maximum circuit voltage.

1 hour ago, TaliaB said:

AC and DC systems rated 600V or less can occupy the same raceway, cable, or enclosure if all conductors have an insulation voltage rating not less than the maximum circuit voltage.

I first wanted to disagree with you, but you do raise an important point.  My house still uses steel conduits.  In new buildings, conduits often carry bare-copper earth wires.  Those earth wires, or the steel conduit,  has zero isolation.  So if one where to run a 12VDC wire with an isolation of only 200V, at first thought, one would expect to be much better off than that bare earth.  However, if that low voltage wire happens to touch/press against a 230VAC (bare) termination at a light switch, wall-socket or similar, then the isolation barrier would not be sufficient.  This is a very likely condition that could happen in a real world scenario.   So seen from that perspective, all wires should carry sufficient isolation to (single handily) withstand the highest voltage carried within the enclosure.

Anyway, it is a moot point for me because I would use normal house wire for the 12VDC circuits.   A requirement for ample isolation is a no-brainer, what irritates me about SANS-10142 is their insistence on AC and DC separation.