Bonding / Termination for Class 2 HVAC control wiring

[Eddie9v]

I am doing an install for 24vac HVAC controls in a northern territory. Class 2 100va. Inspector requested pipe sleeves in wall to protect free air wire, we did this and now he is requesting we bond each one. I bonded each with 14awg to the nearest electrical box but now they are asking for them all to be daisy chained with 10awg bond and then connected to a nearby electrical JB. I also am wiring valves and actuators, typically we install 1110 on duct and do joints in here but I am afraid the inspector is going to make us bond these boxes with 10awg as well... Is there any section of the code that makes me exempt from this. Never had this problem at home. Thanks!

 

[marinkitagawa]

I've run into similar issues in northern projects. Sometimes local inspectors have their own 'addendums' to the code. If they are insisting on a 10awg daisy chain, it might be faster to just comply than to fight it, as 'exemptions' for Class 2 can be vague when it comes to mechanical protection like pipe sleeves.

However, ask him to cite the specific Rule in Section 10 or 16 he is using to justify the 10awg requirement for a 100va load. Usually, 14awg is more than enough for bonding such small enclosures.

 

[DBill64]

Perhaps they are treating them as cable tray:

392.60 Grounding and Bonding.

(A) Metal Cable Trays.
Metal cable trays shall be permitted to be used as equipment grounding conductors where continuous maintenance and supervision ensure that qualified persons service the installed cable tray system and the cable tray complies with this section. Metal cable trays that support electrical conductors shall be grounded as required for conductor enclosures in accordance with 250.96* and Part IV of Article 250. Metal cable trays containing only non-power conductors shall be electrically continuous through approved connections or the use of a bonding jumper.

BUT, conduit sleeves are not cable tray. They would be raceway. Take a look at exception #2 on 250.86:

250.86 Other Conductor Enclosures and Raceways.
Except as permitted by 250.112(I), metal enclosures and raceways for other than service conductors shall be connected to the equipment grounding conductor.
Exception No. 2: Short sections of metal enclosures or raceways used to provide support or protection of cable assemblies from physical damage shall not be required to be connected to the equipment grounding conductor.
(Removed exceptions 1 & 3 to save space. #1 was about knob & tube installations. #3 was about nonmetallic raceways)

Since they are being used for support and protection of limited energy controls only and have nothing to do with the EGC, then I would not believe that they need to be bonded together at all.

If the inspector insists upon bonding the metal conduit sleeves, then instead of trying to fight them on it perhaps the easier solution would be to change them from metal conduit to PVC conduit sleeves. See them try to justify bonding plastic tubes together!

 

[Strathead]

Next time us PVC sleeves.

 

[tortuga]

I am doing an install for 24vac HVAC controls in a northern territory. Class 2 100va. Inspector requested pipe sleeves in wall to protect free air wire, we did this and now he is requesting we bond each one. I bonded each with 14awg to the nearest electrical box but now they are asking for them all to be daisy chained with 10awg bond and then connected to a nearby electrical JB. I also am wiring valves and actuators, typically we install 1110 on duct and do joints in here but I am afraid the inspector is going to make us bond these boxes with 10awg as well... Is there any section of the code that makes me exempt from this. Never had this problem at home. Thanks!

My CEC book is a bit out of date (2018) but from what I recall of Class 2 work in Canada is Rule 12-000 exempts Class 2 wiring methods of Section 12, it does not exempt you from Section 10.
Section 16 generally allows for more flexible wiring methods, but Rule 16-212 emphasizes that Class 2 conductors must be separated from other circuits. If they are installed in a metal raceway, that raceway becomes part of the electrical system's non-current-carrying metalwork and must be bonded per section 10. Then Rules 10-600, 10-606, 10-608 start to kick in, So generally rule 10 requires that the bonding continuity of metal raceways be assured regardless of whats in the raceway, or thats how its been read in the past.
So then your at Rule 10-614 (Size of Bonding Conductor): This is the rule for sizing. It directs you to Table 16 and your #14 should be fine
However Rule 10-116(1): Requires that the conductor be installed such that it is protected from mechanical injury so depending how you run it, the inspector may think #10 is more durable for some reason.
I don't think the inspector can require a #10 but he can require mechanical protection if the #14 is subject to physical damage, you could sleeve the #14 or make sure its protected.
I dont know about the location or environment if say its a plenum / hazardous location over 1000V near by ? So there may be other factors specific to your site triggering obscure rules.
I ran into similar situations doing hazardous location work where class 2 and IS sensors wires were run in underground PVC then switched to rigid metal conduit before they went above ground to a seal off, we pulled a #14 ground wire with the cables to bond the metal junction boxes after the seal off bonding the rest of the non-current-carrying metalwork.

 

[jim dungar]

So generally rule 10 requires that the bonding continuity of metal raceways be assured regardless of whats in the raceway, or thats how its been read in the past.

But a sleeve is not a raceway.
DBill64 laid out a good analysis in post #3.

 

[tortuga]

But a sleeve is not a raceway.
DBill64 laid out a good analysis in post #3.

OP is in Canada so I was using the Canadian Electrical Code (CEC). I have looked for a section like that in the CEC but not found any, my book is a 2018 though.

 

[jim dungar]

OP is in Canada so I was using the Canadian Electrical Code (CEC). I have looked for a section like that in the CEC but not found any, my book is a 2018 though.

Does the CEC call sleeves raceways? I know the NEC says raceways have to be complete, in 300.18 (2017).