SIS wire can't be used in conduit? Technical reasoning?

[ABC789]

I've been told SIS wire can't be used in conduit, only "in" switchgear. However, Houston Wire and Cable spec HW051 says UL Type SIS with XLP Insulation is "for use in power and control circuit in swithboards, control panels, AND recognized raceways." So, can it be used in conduit or not? If not, what is the technical justification. Thanks!

 

[Pierre C Belarge]

SIS cable may not be recognized as a wiring method as per 310.13, and the rest of Chapter 3.
This is a specialty cable.
What is the difficulty with installing THHN/THWN conductors in your application?

 

[ABC789]

SIS wire is historically used in 5kV switchgear wiring due to it's flexibility (#14 has 41 strands). THHN/THWN is too stiff for this application.

 

[ABC789]

XLP is used as insulation on other wires and cable (e.g. instrumentation cable, TC control cable, MV cable, etc.) which are all approved for use in conduit. So,...does anyone have a technical justification why SIS supposedly can't be used in conduit? Thanks

 

[augie47]

To me, the "technical" justification is that "approved" conductors are listed in 310.13 and in that Table SIS is noted as "For Switchboard Wiring Only"

 

[ABC789]

augie47, thank you for reiterating what the code says. However, "for switchboard wiring only" is not a technical justification. If the answer is "no" then I am looking to see if anyone here can offer an insight into the technical justification for this limitation.

 

[ron]

I've heard that SIS does not have an outer jacket, so it cannot withstand the pull through raceway .... and it is not listed in 310.13 for applications other than switchboard wiring.

 

[ron]

Some manufacturers make it dual listed with XHHW which is listed in the NEC 310.13 for use dry and wet locations.
http://www.awcwire.com/ProductSpec.aspx?id=XLPE-Control-Cable-UL-SIS-XHHW-2

 

[ABC789]

Ron, there are other wires that don't have an outer jacket and are approved for conduit. Just looking through HWC catalog here are a few (e.g. XHHW-2,RHW-2, RHH, FEP).

 

[augie47]

augie47, thank you for reiterating what the code says. However, "for switchboard wiring only" is not a technical justification. If the answer is "no" then I am looking to see if anyone here can offer an insight into the technical justification for this limitation.

It's technical enough for me to red tag it

You might check these two Southwire links.
One style does actually have an additional XHHW, RHH listing.

http://www.southwire.com/products/SIS127.htm

http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet301

 

[ABC789]

Thanks Ron. However, one of the main reasons I want to use this is due to the high stranding (41 strands on a #14, from HWC). It's great AWC dual listed it, but they only have 7 strands on a #14. I am looking for the flexibiliy of a higher strand wire.

 

[ABC789]

That is what I'm looking for. Thanks

 

[broadgage]

Perhaps the wire is in fact technicly suitable for installation in conduit, but no one has got around to testing and listing it for that purpose?

Installation in conduit would therefore be safe, but a violation.

Here in the UK we have a type of wire called "tri rated switchgear cable"
This is a single core, multi strand, flexible wire with PVC insulation.
I believe that it is UL listed, and also approved to UK and EU standards, it is mainly used in the manufacture of equipment that may be used in, or exported to, various countries.

I believe that the UL listing only covers use in appliances and equipment, not conduit.

 

[ABC789]

I talked with Southwire regarding their XHHW/SIS dual listed product line and they said it meets the XHHW requirments of table 310.13, thus it is suitable for use in conduit. Model number 564929 for black #14 with 41 strand.

http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet301

 

[brian john]

But in a SWBD give me SIS, looks better and handles like a charm, great for going from swbd to door mounted metering.

 

[SG-1]

Houston Wire and Cable spec HW051 says UL Type SIS with XLP Insulation is "for use in power and control circuit in swithboards, control panels, AND recognized raceways." So, can it be used in conduit or not? If not, what is the technical justification. Thanks!

I am thinking the only raceway for SIS is a wire trough.

Technical justification is the insulation will not fair well through bends in conduit. The Southwire page referenced does not list raceways in the Product Application for standard SIS.

The UL Type SIS/XHHW-2 VW-1 looks like it is good to go for conduit. How flexible it is I do not know.

 

[LarryFine]

. . . Houston Wire and Cable spec HW051 says UL Type SIS with XLP Insulation is "for use in power and control circuit in swithboards, control panels, AND recognized raceways."

So, get them to send you whatever proof your AHJ requires to permit your use of it.

 

[weressl]

I've heard that SIS does not have an outer jacket, so it cannot withstand the pull through raceway .... and it is not listed in 310.13 for applications other than switchboard wiring.

Neither does XHHW or RHH, etc., but it could be that the SIS is a softer compound and it is not reguired to be tested for pulling abrasion.