Wire Sharing in Conduit

[DPC]

This is tech cable, you guys will never deal with it, but I want to explain something..

Sometimes I have to wire up a 600 volt motor and its always a lot of trouble to pull multiple armoured cables like this.
So sometimes ( when the planner is on the ball ) he will order tech with all the wires in need in it.
It will have the three power conductors and bond of course and three control wires for control ( seems pretty obvious )

Other times I will use another tech cable with identical wires 3, 4, 7 , 9, 12....
All these wires are rated for 600 or 1000 volt and this is perfectly except able.
I can run 600 with 24 vdc control or automation inputs all kinds of things.
This is allowed!

BUT you need to be very careful.
Sometimes induced noise will cause some problems.
This is not a code problem this is a noise problem.
I would not run a Modbus cable in a conduit with anything thats going to generate RF like an inverter or MPPT controller.
But everything else is fair game

So in those rare cases I run separate cables or if Im using a conduit I will run a shielded cable and run it separate.

Maybe its different in the USA, but the majority of the time you buys spool of wire, its rated at 600 volt.
No issues...
But if it makes you feel better run more conduits.

 

[crws]

Kick starting this again, with focus on the EG4 All Weather conduit box.

Anyone having compliance issues running battery, Inverter A/C output, Array DC input, and comms together in these boxes?

Based on my interpretation of the 2023 code, as long as at least 1 zip tie (every 6ft) groups the DC circuit and AC circuit harnesses separately, this satisfies 690.31(B)?
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PV system dc circuit conductors cannot be installed in the same enclosure, cable, or raceway with inverter ac output circuit conductors or other conductors unless separated by a barrier or partition.

Ex. Where all conductors or cables have an insulation rating equal to at least the maximum circuit voltage applied to any conductor, then:
(1) Multiconductor jacketed ac cables can be in the same enclosure with dc circuits where all circuits serve the PV system.
(2) Inverter output ac circuits can be in the same enclosure or wireway with PV system dc circuits that are identified and grouped per 690.31(B)(2) and (B)(3).

PV system dc and ac conductors in the same enclosure or wireway must be grouped separately with cable ties or similar means at least once and at intervals not to exceed 6 ft [690.31(B)(3)]
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Secondarily,
My comms cable is 300v rated, and technically- only the DC input would exceed 300v(but has 600v rated THHN), but I'm not sure of the delineation between "conduit" and "enclosure" where the rating would need to equal that of THHN as in conduit, ie. Home Run, provided that both would be grouped separately and labeled inside the enclosure.

@robbob2112 @sumpower

 

[chill633]

Enclosures house equipment, conduit houses cable/wire. Conduit Bodies are separate portion of a conduit or tubing system that provides access through a removable cover(s) to the interior of the system at a junction of two or more sections of the system or at a terminal point of the system.

The EG4 Conduit Box is therefore a Conduit Body as defined in NEC 2023.

Are your AC and DC wires all entering the conduit box via the same hole? Because 690.31(B)(3) had the following exception:

Exception: The requirement for grouping shall not apply if the circuit enters from a cable or raceway unique to the circuit that makes the grouping obvious.

To nitpick, your comms cable needs to have an insulation rating higher than the highest DC voltage coming in. You can probably mitigate that by wrapping it in some MC sheath, which will provide a barrier. You can buy hollow MC sheath at places like Home Depot and Lowe's. You should only have to wrap the short part that's in the conduit body. Assuming you have a very picky AHJ.

 

[crws]

Enclosures house equipment, conduit houses cable/wire. Conduit Bodies are separate portion of a conduit or tubing system that provides access through a removable cover(s) to the interior of the system at a junction of two or more sections of the system or at a terminal point of the system.

The EG4 Conduit Box is therefore a Conduit Body as defined in NEC 2023.

Are your AC and DC wires all entering the conduit box via the same hole? Because 690.31(B)(3) had the following exception:

Exception: The requirement for grouping shall not apply if the circuit enters from a cable or raceway unique to the circuit that makes the grouping obvious.

To nitpick, your comms cable needs to have an insulation rating higher than the highest DC voltage coming in. You can probably mitigate that by wrapping it in some MC sheath, which will provide a barrier. You can buy hollow MC sheath at places like Home Depot and Lowe's. You should only have to wrap the short part that's in the conduit body. Assuming you have a very picky AHJ.

All circuits enter from their dedicated pathways. No mixing at points of entry into the EG4 box.
I ordered some 600v rated ethernet, but the jacket on what I got is so thick it won't fit into my EZ-44 RJ45 connectors.
I did consider adding 3/4 LFMC through the 200A section of the box, although it would be a pia to do 2 interior terminations onto exterior pvc terminations

 

[chill633]

I ordered some 600v rated ethernet, but the jacket on what I got is so thick it won't fit into my EZ-44 RJ45 connectors.

You needed to order compatible connectors as well. This is the route I went, but mostly because I had a bunch of 600V, direct-bury CAT-6A laying around.

 

[crws]

You needed to order compatible connectors as well. This is the route I went, but mostly because I had a bunch of 600V, direct-bury CAT-6A laying around.

Hmmm.
I hastily ordered the first 600v cable that looked good. LoL
Found some 24awg Cat8 connectors that fit 8mm diameter. We'll see how that goes. SMH.
Thanks.
What's a few extra bucks when you've dropped 25k.
I'll have a few extra receipts for tax day.

 

[sumpower]

Enclosures house equipment, conduit houses cable/wire. Conduit Bodies are separate portion of a conduit or tubing system that provides access through a removable cover(s) to the interior of the system at a junction of two or more sections of the system or at a terminal point of the system.

The EG4 Conduit Box is therefore a Conduit Body as defined in NEC 2023.

Are your AC and DC wires all entering the conduit box via the same hole? Because 690.31(B)(3) had the following exception:

Exception: The requirement for grouping shall not apply if the circuit enters from a cable or raceway unique to the circuit that makes the grouping obvious.

To nitpick, your comms cable needs to have an insulation rating higher than the highest DC voltage coming in. You can probably mitigate that by wrapping it in some MC sheath, which will provide a barrier. You can buy hollow MC sheath at places like Home Depot and Lowe's. You should only have to wrap the short part that's in the conduit body. Assuming you have a very picky AHJ.

I used to be that picky AHJ, nothing wrong with what you are saying here. But that MC sheath wrap I have never heard of, so I learn something new. I have seen flexible metal conduit used though. The only problem with a metalic "sheath wrap" is that it must be bonded to the rest of the metal enclosure at some point, so it would need to terminate to the enclosure in an aproved method.

 

[crws]

I used to be that picky AHJ, nothing wrong with what you are saying here. But that MC sheath wrap I have never heard of, so I learn something new. I have seen flexible metal conduit used though. The only problem with a metalic "sheath wrap" is that it must be bonded to the rest of the metal enclosure at some point, so it would need to terminate to the enclosure in an aproved method.

The mongo 6a 600v cable I originally bought has both a foil shield and braid, which in reality from what I understand have no bearing with grounding, primarily emi rejection, so if the larger connectors I ordered are a go, I will run that with some labeling and zip ties and see what our local has to say.
Prelimin was happy, I can imagine a lot of hacking rn trying to pack work into the last month.
Other than that, I have Cat5 600v shielded of smaller diameter on order that will fit my current supply of pass through RJ45 connectors.
TY

 

[zanydroid]

I used to be that picky AHJ, nothing wrong with what you are saying here. But that MC sheath wrap I have never heard of, so I learn something new. I have seen flexible metal conduit used though. The only problem with a metalic "sheath wrap" is that it must be bonded to the rest of the metal enclosure at some point, so it would need to terminate to the enclosure in an aproved method.

Can’t you just use a bonding fitting that has a lay in EGC lug?

I dare say you could even go with interference fit kind of retention. Or rather, cut it 2” or whatever shorter than the cable its protection , stack some fittings at one end to bond

This will provide pretty robust isolation IMO even though it’s not a complete conduit system

Or maybe use LFNC and not even bond

Listed devices and controls panels do NOT need full enclosure of the low voltage / high voltage components from each other. It doesn’t even need to be IP20! Plastic gates and clips with holes in them are fine. From what I’ve seen of devices that have stuff like line voltage and Ethernet in the same device. Granted you have more dispensation for a listed device

 

[chill633]

The mongo 6a 600v cable I originally bought has both a foil shield and braid, which in reality from what I understand have no bearing with grounding, primarily efi rejection, so if the larger connectors I ordered are a go, I will run that with some labeling and zip ties and see what our local has to say.
Prelimin was happy, I can imagine a lot of hacking rn trying to pack work into the last month.
Other than that, I have Cat5 600v shielded of smaller diameter on order that will fit my current supply of pass through RJ45 connectors.
TY

There should be a wire inside that for grounding, ground one end of the wire, not both. Both will create a ground loop and interference. Not grounding either end creates an antenna.

For the RSD wire that isn't a problem, because that isn't a signal it is just a voltage. But for a comms wire or rs485 it can create problems.

 

[chill633]

I used to be that picky AHJ, nothing wrong with what you are saying here. But that MC sheath wrap I have never heard of, so I learn something new. I have seen flexible metal conduit used though. The only problem with a metalic "sheath wrap" is that it must be bonded to the rest of the metal enclosure at some point, so it would need to terminate to the enclosure in an aproved method.

Thanks. The packet I bought came with a pair of connector ends. They both protect against the sharp edges and provided a screw to attach a grounding wire to. I just stubbed a bare #12 solid to the ground bar in the FB.

 

[Wombat Ranger]

How would one measure aforementioned inductive currents? I have a pair of DC wire + ground running from my house side mounted combiner to the power system location DIRECTLY on top of the AC feed from main panel back to the house. Direct buried, no conduit underground, both are exactly the same wire, as in, off the same spool.

No issues that we have observed.

 

[zanydroid]

How would one measure aforementioned inductive currents? I have a pair of DC wire + ground running from my house side mounted combiner to the power system location DIRECTLY on top of the AC feed from main panel back to the house. Direct buried, no conduit underground, both are exactly the same wire, as in, off the same spool.

No issues that we have observed.

The ground loop being discussed is for interfering with the small signals (digital in this case, but it is also relevant for audio signals)

AFAIK the only induction you care about for power level situations, is inductive heating from not running the two parts of an AC circuit through the same conduit / breaking eddy loops when crossing out of a metal box

This sounds complicated, but it’s not important to understand if you follow code sanctioned wiring methods instead of making shit up

 

[chill633]

This sounds complicated, but it’s not important if you follow code sanctioned wiring methods instead of making shit up

Blasphemy!

 

[Wombat Ranger]

The ground loop being discussed is for interfering with the small signals (digital in this case, but it is also relevant for audio signals)

AFAIK the only induction you care about for power level situations, is inductive heating from not running the two parts of an AC circuit through the same conduit / breaking eddy loops when crossing out of a metal box

This sounds complicated, but it’s not important to understand if you follow code sanctioned wiring methods instead of making shit up

I should have quoted this post to reference to my question.

Running AC and DC wiring side by side will induce an ac voltage on the dc line because of the magnetic field from current flowing.... this is how a transformer works..except a transformer is two windings or more around a iron or other core...

You want to run the ac and DC lines in different conduit 14 inches apart... the same goes for data cables ideally...

How would one measure aforementioned inductive currents? I have a pair of DC wire + ground running from my house side mounted combiner to the power system location DIRECTLY on top of the AC feed from main panel back to the house. Direct buried, no conduit underground, both are exactly the same wire, as in, off the same spool.

No issues that we have observed.

 

[sumpower]

Can’t you just use a bonding fitting that has a lay in EGC lug?

If the MC sheath cable is available, which I interpret as the steel or aluminum outer portion of MC cable that has no conductors inside.
Then an MC cable connector would provide an approved grounding path for the metal sheath. The approved for the purpose part in an above post.
A lay-in-lug would then not be needed.

I dare say you could even go with interference fit kind of retention. Or rather, cut it 2” or whatever shorter than the cable its protection , stack some fittings at one end to bond

This will provide pretty robust isolation IMO even though it’s not a complete conduit system

Or maybe use LFNC and not even bond

Listed devices and controls panels do NOT need full enclosure of the low voltage / high voltage components from each other. It doesn’t even need to be IP20! Plastic gates and clips with holes in them are fine. From what I’ve seen of devices that have stuff like line voltage and Ethernet in the same device. Granted you have more dispensation for a listed device

 

[zanydroid]

If the MC sheath cable is available, which I interpret as the steel or aluminum outer portion of MC cable that has no conductors inside.
Then an MC cable connector would provide an approved grounding path for the metal sheath. The approved for the purpose part in an above post.
A lay-in-lug would then not be needed.

I meant a MC cable connector that has the lay in lug in it, and instead of bonding via a nut to the box , which is a firm connection, just leave the sleeve floating in the middle of the cable. Lay in lug would then bond via an appropriate green conductor to a grounding point