Understanding Differences Between RHH/RHW-2 & XHHW/XHHW2 Building Wire
RHW and XHHW/XHHW2 are the two commonly confused cable ratings that indicate a specific type of building wire. In fact, these two are more similar than different. One of those is the general cable rating, whereas the other is the particular cable type. To fully understand the differences between the two, read this short blog.
RHW vs. XHHW/XHHW2: How Do They Overlap?
RHW translates to a high-heat rubber insulation cable that is resistant to water. If the cable is named RHH, it has the same characteristics except that it is not water-resistant. The "R" in the name of the cable indicates that the insulation is made of rubber. RHW-2 indicates the temperature rating of 90 C, whereas if the cable is simply rated as RHW, it has a temperature rating of 75 C.
XHHW/XHHW2 has XLPE (cross-linked polyethylene) insulation that fits under the umbrella of rubber insulations. Therefore, all XHHW/XHHW2 cables are technically RHW. However, not all RHW cables have the same insulation as XHHW/XHHW2, so the main thing differentiating this cable is the specific properties of cross-linked polyethylene insulation. XHHW cable has a temperature rating of 75 C, whereas XHHW2 stands for 90 C.
RHW vs. XHHW/XHHW2: What's Different?
Judging from the properties of cross-linked polyethylene insulation as opposed to rubber insulations in general, here are the few characteristics that make XHHW/XHHW2 stand out among other RHH/RHW-2 cables.
- XLPE insulation is lighter than other rubber insulations, making XHHW/XHHW2 one of the most lightweight RHH/RHW-2 cables.
- XHHW/XHHW2 is easier to pull than other rubber cables, especially in low temperatures, where other rubber insulations may perform quite badly.
- For low-leakage electrical circuits, XHHW/XHHW2 is the preferred type of rubber-insulated cables.
RHH/RHW-2 As A Rating That Applies To Different Cables
RHH is a standard rating given to many different cables since many cables share the properties of being resistant to heat and having rubber insulation. It is common for cables to be double-rated as RHH/RHW-2. Therefore, RHH/RHW-2 is a standard cable rating rather than a specific cable type.
These cables are often rated as USE-2, which is applicable for underground service. MTW machine tool wire, welding cables, and diesel locomotive cables are often double-rated RHH/RHW-2. In the case of the latter two, RHH/RHW-2 rating allows them to be used in applications required by the National Electric Code.
At Nassau National Cable, you may purchase copper XLP USE-2 cables double-rated as RHH RHW-2, aluminum RHH RHW-2 cables, copper XHHW-2 cables, and aluminum XHHW-2 cables at some of the best prices in the industry.
