MC cable in wet location

[gpipia]

When installing MC cable indoors can it be sleeved in non metallic tubing with anti short bushing when penetrating exterior wall to a generator?
The wire (THHN) from the MC would be in the non metallic tubing or is this still considered wet location for MC?

 

[Smart $]

When installing MC cable indoors can it be sleeved in non metallic tubing with anti short bushing when penetrating exterior wall to a generator?
The wire (THHN) from the MC would be in the non metallic tubing or is this still considered wet location for MC?

The wall itself may be considered a damp location, and beyond the exterior is definitely a wet location (unless covered or such). Conductors therein and thereon must be suitable for the condition.

However, you did not state the type of MC cable. PVC-jacketed MC cable such as Southwire's Armorlite is rated for wet locations.

 

[goldstar]

I agree with Smart $ for the most part. I think another issue would be termination of the MC and not so much the rating of the conductors. They are peoperly markes as THHN. The MC is properly terminated at beginning end but if I'm reading you correctly it's only being sleeved through the PVC. If you use a female adapter before going into the PVC you can terminate the MC there and then sleeve just the conductors through the PVC and not the MC jacket.

 

[Smart $]

I agree with Smart $ for the most part. I think another issue would be termination of the MC and not so much the rating of the conductors. They are peoperly markes as THHN. The MC is properly terminated at beginning end but if I'm reading you correctly it's only being sleeved through the PVC. If you use a female adapter before going into the PVC you can terminate the MC there and then sleeve just the conductors through the PVC and not the MC jacket.

THHN is not suitable for wet locations.

 

[goldstar]

THHN is not suitable for wet locations.

That's not what Southwire says :

http://www.southwire.com/support/THHNGuideSpecifications.htm

THHN Guide Specifications

Annex A Type THHN Conductor Specification
26 05 19 WIRE AND CABLE TYPE THHN

PART 1 ? GENERAL

1.1 ? SPECIFICATION INCLUDES

1.1.1 Cable Type: Type THHN/THWN for use as services, feeders and branch circuits

1.1.2 General Applications: Type THHN/THWN cable may be used in the following general applications per the National Electrical Code?

1.1.2.1 In Conduit

1.1.2.2 In Cable Tray

1.1.2.3 For Services

1.1.2.4 For Feeders

1.1.2.5 For Branch Circuits

1.1.2.6 Wet or Dry Locations

 

[kwired]

That's not what Southwire says :

http://www.southwire.com/support/THHNGuideSpecifications.htm



THHN Guide Specifications

Annex A Type THHN Conductor Specification
26 05 19 WIRE AND CABLE TYPE THHN

PART 1 ? GENERAL

1.1 ? SPECIFICATION INCLUDES

1.1.1 Cable Type: Type THHN/THWN for use as services, feeders and branch circuits

1.1.2 General Applications: Type THHN/THWN cable may be used in the following general applications per the National Electrical Code?

1.1.2.1 In Conduit

1.1.2.2 In Cable Tray

1.1.2.3 For Services

1.1.2.4 For Feeders

1.1.2.5 For Branch Circuits

1.1.2.6 Wet or Dry Locations

That specification is for THHN/THWN combination rated conductor. Chances are that is about all you will ever find without special ordering is the dual rated version. A conductor without dual ratings and THHN only is not a wet location conductor. A conductor that is only rated THHN/THWN is also a 90C conductor dry and a 75C conductor wet. If it has the "-2" suffix then it can be used at 90C wet.

Since we are talking MC cable though the conductors installed in the cable may or may not be marked, and there is no promises they will be marked with dual rating either, unless maybe it is a wet location rated cable assembly.

 

[Smart $]

That specification is for THHN/THWN combination rated conductor. Chances are that is about all you will ever find without special ordering is the dual rated version. A conductor without dual ratings and THHN only is not a wet location conductor. A conductor that is only rated THHN/THWN is also a 90C conductor dry and a 75C conductor wet. If it has the "-2" suffix then it can be used at 90C wet.

Agree... regarding single conductors. I haven't used MC in a long time and have none readily available to check.... are [basic] MC conductors marked just THHN or THHN/THWN(-2)?

 

[kwired]

Agree... regarding single conductors. I haven't used MC in a long time and have none readily available to check.... are [basic] MC conductors marked just THHN or THHN/THWN(-2)?

Most of the cable I have used the conductors are not marked, but sometimes they are, but not certain what marking they had though.

 

[Sean C.]

What connector do you use a carflex connector? Or a Mc connector? At your generator. I would say just set a 4square inside, then come out of the back with carflex with thhn/thwn.

 

[goldstar]

Agree... regarding single conductors. I haven't used MC in a long time and have none readily available to check.... are [basic] MC conductors marked just THHN or THHN/THWN(-2)?

Not sure. I'd have to look.

Most of the cable I have used the conductors are not marked, but sometimes they are, but not certain what marking they had though.

Possibly the smaller sizes (#'s 12 & 14) but on larger sizes thay are marked.

 

[goldstar]

What connector do you use a carflex connector? Or a Mc connector? At your generator. I would say just set a 4square inside, then come out of the back with carflex with thhn/thwn.

I like your way better but you can also use this combination :

http://www.cooperindustries.com/con..._mc/acb_series_connectorsforacmcfittings.html

http://www.grainger.com/product/CANTEX-Female-Adapters-4FYA3

 

[goldstar]

Is the OP's situation considered a damp location ? It sounds like it's going to be inside PVC or flex PVC to the generator. If we look at :

310.10 Uses Permitted.
The conductors described in 310.104 shall be permitted for use in any of the wiring methods covered in Chapter 3 and as specified in their respective tables or as permitted elsewhere in this Code.

(B) Dry and Damp Locations. Insulated conductors and cables used in dry and damp locations shall be Types FEP, FEPB, MTW, PFA, RHH, RHW, RHW-2, SA, THHN, THW, THW-2, THHW, THWN, THWN-2, TW, XHH, XHHW, XHHW-2, Z, or ZW.

(C) Wet Locations. Insulated conductors and cables used in wet locations shall comply with one of the following:
(1) Be moisture-impervious metal-sheathed
(2) Be types MTW, RHW, RHW-2, TW, THW, THW-2, THHW, THWN, THWN-2, XHHW, XHHW-2, ZW
(3) Be of a type listed for use in wet locations.

I know I made an assumption here but if it's above ground and in a flexible whip to the generator I believe THHN can be used. If it's submersed or in PVC underground to the generator then I would agree that it cannot be used as that conduit could fill with water or condensation.

I'm also having some trouble understanding the wire marking requirements. If we look at Southwire's specs on THHN we find the following :

THHN/THWN/TWN75/T90

• 600 Volt
• Copper Conductor
• Thermoplastic Insulation/Nylon Sheath. Heat, Moisture, Gasoline, and Oil Resistant1
• Sizes 14 AWG through 6 AWG Rated AWM. (105?C) Sizes 14 AWG through 1 AWG Rated VW-1.

Applications

• Southwire Type THHN or THWN-2* conductors are primarily used in conduit and cable trays for services, feeders, and branch circuits in commercial or industrial applications as specified in the National Electrical Code?2
• When used as Type THHN, conductor is suitable for use in dry locations at temperatures not to exceed 90?C
• When used as Type THWN-2*, conductor is suitable for use in wet or dry locations at temperatures not to exceed 90?C or not to exceed 75?C when exposed to oil or coolant
• When used as Type MTW, conductor is suitable for use in wet locations or when exposed to oil or coolant at temperatures not to exceed 60?C or dry locations at temperatures not to exceed 90?C (with ampacity limited to that for 75?C conductor temperature per NFPA 79)
• Conductor temperatures not to exceed 105?C in dry locations when rated AWM and used as appliance wiring material. Voltage for all applications is 600 volts

If THHN is cross listed as THWN or MTW why can't it be used in wet locations ? Someone please educate me. Thanks.

 

[kwired]

Is the OP's situation considered a damp location ? It sounds like it's going to be inside PVC or flex PVC to the generator. If we look at :

I know I made an assumption here but if it's above ground and in a flexible whip to the generator I believe THHN can be used. If it's submersed or in PVC underground to the generator then I would agree that it cannot be used as that conduit could fill with water or condensation.

I'm also having some trouble understanding the wire marking requirements. If we look at Southwire's specs on THHN we find the following :
If THHN is cross listed as THWN or MTW why can't it be used in wet locations ? Someone please educate me. Thanks.

It can be used in wet locations if it has both markings on it.

THHN marking only is a dry location conductor.

MC cable with no marking at all on it's conductors is not able to be used with sheath removed and installed in a raceway either though, as that conductor has no rating for use outside the cable it comes with.

 

[Smart $]

...
MC cable with no marking at all on it's conductors is not able to be used with sheath removed and installed in a raceway either though, as that conductor has no rating for use outside the cable it comes with.

I disagrrrrree. For one, when not marked on conductors, it may be stated in manufacturer documentation. For example:

http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheetOEM24

Aside from that, what Code requirement(s) state it is not permitted... explicitly?

 

[kwired]

I disagrrrrree. For one, when not marked on conductors, it may be stated in manufacturer documentation. For example:

http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheetOEM24

Aside from that, what Code requirement(s) state it is not permitted... explicitly?

We have this discussion all the time about the conductors inside NM cable, why should other cable types be any different?

Unless the individual conductors are marked with a type listed in 310.104 which is referenced by 310.10 they are not permitted to be used by NEC. Conductors that are part of a listed cable assembly such as NM or MC cable are acceptable as long as they are a part of the assembly they were a part of. Remove them from the cable assembly though and they are not acceptable conductors by 310.10 - 310.104 unless they have required marking on them that is required by 310.120.

 

[Smart $]

We have this discussion all the time about the conductors inside NM cable, why should other cable types be any different?

Unless the individual conductors are marked with a type listed in 310.104 which is referenced by 310.10 they are not permitted to be used by NEC. Conductors that are part of a listed cable assembly such as NM or MC cable are acceptable as long as they are a part of the assembly they were a part of. Remove them from the cable assembly though and they are not acceptable conductors by 310.10 - 310.104 unless they have required marking on them that is required by 310.120.

The usual issue with NM is the termination of its sheath when entering a raceway. If the sheath is properly terminated, I have no issue with stripped NM in a raceway.

The Code does not actually say that. It says...

310.10 Uses Permitted. The conductors described in
310.104 shall be permitted for use in any of the wiring
methods covered in Chapter 3 and as specified in their
respective tables or as permitted elsewhere in this Code.

Here's another along the same line...

300.3 Conductors.

(A) Single Conductors. Single conductors specified in
Table 310.104(A) shall only be installed where part of a
recognized wiring method of Chapter 3.

In effect, its saying you cannot use individual conductors without being installed in a raceway or other type of protective enclosure. It is not saying the only individual conductors that can be used are described in 310.104. Type MC Cable is a Chapter 3 wiring method. As such, its individual conductors are permitted to be used, or else you would not be able to terminate them without a special adapter/connector.

If individual conductors of a cable are permitted/recognized by the NEC in cabinets, enclosures, junction boxes, etc., it stands to reason they are permitted in raceways. Show me a requirement which states otherwise.

310.120 does not require individual conductors of Type MC Cable to be marked.

 

[kwired]

The usual issue with NM is the termination of its sheath when entering a raceway. If the sheath is properly terminated, I have no issue with stripped NM in a raceway.

The Code does not actually say that. It says...



Here's another along the same line...



In effect, its saying you cannot use individual conductors without being installed in a raceway or other type of protective enclosure. It is not saying the only individual conductors that can be used are described in 310.104. Type MC Cable is a Chapter 3 wiring method. As such, its individual conductors are permitted to be used, or else you would not be able to terminate them without a special adapter/connector.

If individual conductors of a cable are permitted/recognized by the NEC in cabinets, enclosures, junction boxes, etc., it stands to reason they are permitted in raceways. Show me a requirement which states otherwise.

310.120 does not require individual conductors of Type MC Cable to be marked.

This has come up many times before, usually involving NM cable and someone wanting to strip the sheath and run the conductors (from the NM cable) in a raceway for whatever reason. The majority of responses to this is that those conductors - though they are supposed to be 90 deg conductors, are not necessarily THHN, unless they would happen to be marked as required, they are not recognized to use other than with the cable they are a part of, now stripping the sheath to expose conductors when entering enclosures is not the same as running in a raceway. Why would MC cable or any other cable be any different, other than the fact that you sometimes do find conductors with proper marking inside some cables?

 

[Smart $]

... now stripping the sheath to expose conductors when entering enclosures is not the same as running in a raceway. ...

While I agree that is the general consensus, what Code prohibits it?

I realize 334.15(C) requires the sheath to extend into the outlet or box at the other end of the raceway, but the cable is not required to be securely terminated where it enters the raceway.

 

[kwired]

While I agree that is the general consensus, what Code prohibits it?

How about the rest of 310.10, in particular:

(A) Dry Locations. Insulated conductors and cables used in dry locations shall be any of the types identified in this Code.

(B) Dry and Damp Locations. Insulated conductors and cables used in dry and damp locations shall be Types FEP, FEPB, MTW, PFA, RHH, RHW, RHW-2, SA, THHN, THW, THW-2, THHW, THWN, THWN-2, TW, XHH, XHHW, XHHW-2, Z, or ZW.

(C) Wet Locations. Insulated conductors and cables used in wet locations shall comply with one of the following:
(1) Be moisture-impervious metal-sheathed
(2) Be types MTW, RHW, RHW-2, TW, THW, THW-2, THHW, THWN, THWN-2, XHHW, XHHW-2, ZW
(3) Be of a type listed for use in wet locations

A - seems to tell us for dry locations they need to be a type recognized by the code.
B and C actually tell us they need to be specific types for those applications.

 

[goldstar]

I guess we need to determine if the PVC going thru the wall maybe to a disconnect or the (above ground) flex PVC from the disconnect going out to the generator is considered a wet or damp location.