Common Types of RV Propane Fittings

What are the Common Types of Propane Fittings Used on RVs?

If there's one thing that's simple and straightforward on RVs, it's propane fittings—said no one ever. It's no wonder propane fittings can be so confusing. There are half a dozen different types, and they all do different things. Some connect to your regulator, some connect directly to your tank, and some are found on hoses, T-fittings, and adapters. Because of this, it can be difficult to tell what fittings you have or what you need to do the job at hand, whether that's replacing a part, connecting a gas grill, adding an extension hose, or modifying your system in some other way. In fact, we get so many questions on propane fittings, we created this guide to clear up the confusion, help you identify what fittings you're looking at, and help you understand what they do. We're not sure who decided propane fittings were supposed to be complicated, but we respectfully disagree—we'll break it all down for you below so you can become a propane fitting guru. Or you know, at least hook up your grill or use your water heater, because that's what you're really here for. Let's do this!

Types OF RV Propane Fittings

We'll start by laying it all out there; there are 7 main categories of RV fittings. (If none of them ring a bell for you, don't worry. We'll explain.)
  • POL Fittings
  • Type 1 (ACME) Fittings
  • Inverted Flare Fittings
  • NPT Fittings
  • Flare Fittings
  • Quick-Disconnect Fittings
  • 1"-20 (Disposable Cylinder Port) Fittings
RV propane fittings have both male and female ends, and sometimes the fittings come in more than one size. So yes, there are a lot of potential combinations. The three main criteria to look at when identifying a fitting are these: 1. Where is the fitting located? For instance, is it connected to a regulator or a tank? Is it located on a supply hose or a portable accessory? Although there is some overlap, propane setups generally use different fitting types for different purposes. The fitting's location on your setup is going to give you the biggest clue as to what it is. 2. Is the fitting male or female? This is usually easy to determine just by looking at the fitting. Again, propane setups generally use different types for different purposes. 3. What size is the fitting? Some fittings are universal (for instance, there's only one size of POL fitting). However, other fittings like NPTs and flares come in different diameters. Some of these will be more common than others and will be used in different locations. We've included a chart with the exact thread diameters in case it comes down to measuring your fitting. Armed with this knowledge, you'll be able to identify pretty much any fitting you come across.
Thread Diameters for NPT, Flare, and Inverted Flare Fittings
POL and Type 1 Fittings
Inverted Flare and NPT Fittings
Flare and Quick-Disconnect Fittings
1"-20 Propane Fittings
So...What Type of Fitting Do I Have? Let's take a look at the most common RV propane fittings, what they look like, and where they're usually located. Nine times out of ten, this is all you need to identify what type of fitting you have and what you need. The biggest clue when identifying a fitting is going to be its location. Where is the fitting you're trying to identify?
On the tank: If the fitting is located on your actual tank, it's most likely a POL or Type 1 fitting. The female fittings are on the tank itself, and the male fittings connect to them.You'll be able to easily tell whether you have a POL or Type 1 fitting just by looking at it. Type 1 fittings have a distinguishable colored connector that allows you to hand-tighten them. Type 1 fittings also run on the outside of the tank valve, while POL threads run on the inside.You're most likely to find POL fittings on non-removable motorhome propane tanks. These fittings will connect the tank itself to the regulator. On the other hand, you'll likely find Type 1 fittings on removable propane tanks on fifth wheels and travel trailers. These fittings will connect the tank to the pigtail hose (which then feeds into the regulator). If you'd like to connect a tee fitting to your setup, you can typically do it here by adding the tee between your tank and regulator. You'll need a tee with the appropriate fitting (either POL or type 1) to connect to the tank side.
RV Propane Tank with POL Fittings
RV Propane Tank with Type 1 Fittings
Hose Going Into RegulatorLooking at your pigtail hose where it attaches to your regulator? You're most likely looking at a 1/4" NPT fitting or inverted flare fitting. (The female end is located on the regulator, ad the male end is on the hose.) NPT fittings are found on most regulators, whether they're single or dual stage. The exceptions are auto-changeover regulators, which automatically switch your fuel source from one propane tank to another when the first runs out. These regulators have female inverted flare fittings (called FIF fittings), and they attach to male inverted flare (MIF) hoses. Not sure what type of regulator you have? Here's a quick reference point: if your regulator has a gold adapter fitting, it has a FIF fitting and requires a MIF hose. If it does not have a gold adapter, it has a 1/4" female NPT fitting and requires a 1/4" male NPT hose. You can also tell the difference between male NPT and inverted flare fittings by looking at their thread size. The circumference of MIF threads becomes narrower, while the circumference of NPT threads does not (see image below). NOTE: You might see male and female NPT fittings referred to as "MPT" and "FPT" fittings, respectively. These are interchangeable with "NPT," so don't be alarmed if you see these abbreviations at times.
Male NPT Fitting vs Male Inverted Flare Fitting
Standard Regulator vs Auto Changeover Regulator
Male NPT fitting on pigtail hose attached to female NPT fitting on regulator
Inverted Flare Fittings
Hose Coming Out of RegulatorThe hose coming out of your regulator and bringing propane to your appliances will usually have a 3/8" NPT fitting. The female end is located on the regulator, and the male end is located on the supply hose.
Male NPT hose into female NPT regulator connection on propane tank

Supply Hose Connected to Main Propane Line

The fitting that attaches your supply hose to your RV's main propane line will typically be a 1/2" or 3/8" flare fitting. (NOTE: these are different than inverted flare fittings and belong to their own category.) The female ends are usually found on the supply-hose end, while the male fittings are usually found on the main line itself.
Male and female flare fittings connecting a propane supply hose to main propane line on RV

Tee Fitting, Grill, Outdoor Kitchen, or Accessory Port

Do you have a weird fitting sticking off your RV or accessory and you're not sure what it is? It might be a Quick-Disconnect, or QD fitting. You can often find these fittings anywhere you might temporarily hook up an accessory and later remove it, and that's because QD fittings are extremely easy to connect and disconnect. They're often found in outdoor kitchens so you can connect propane grills or fire pits. They're also often found on tees.
Quick-Disconnect Fitting Diagram - Hose Connected to Grill
Quick-Disconnect Fitting Diagram - Hose Connected to Grill
Quick-Disconnect Fitting Diagram - Hose Connected to Tee

Portable Propane Cylinder

Do you use throwaway propane cylinders for your grill or other propane accessory? Or maybe you want a disposable tank as backup if you run out of fuel? Your disposable cylinder most likely came with a male 1"-20 fitting (also called a disposable cylinder port). This 1"-20 fitting attaches to a hose with a 1"-20 female connector.
Quick-Disconnect Fitting Diagram - Hose Connected to Grill
So, to recap, the best way to identify what propane fitting you have or need is to look at its location. Determine if it's a male or female fitting and what size it is, if more than one size is available. From there, you should be able to connect a gas grill, hook up an external propane tank, or hook up whatever propane setup you can imagine. And if you're still not sure and have a question about your specific setup, go ahead and leave your question in the comment section below! We're happy to help take the "pain" out of "propane" any way we can.
Amber S.
About Amber S.As a content writer for etrailer, I might spend my morning loading and unloading a bike on five different bike racks to figure out which is easiest to use. I might be in the parking lot, taking pictures of an impressive RV battery setup our techs came across in the shop and discussing the benefits of the setup with the owner. I might spend an afternoon in a manufacturer training class for some hands-on experience with new products, and then sit down to assemble all this information into a coherent article. At etrailer, one of our core values is that we are always learning, and I learn something new every day. I start each morning with the goal in mind of taking all of this information and figuring out the best way to answer the questions people ask us (and the ones they don’t know to ask yet), and helping people get the solutions they need to make their lives easier, safer, and more fun. I’m a DIYer at heart, so it brings me great joy to help a fellow DIYer find what they’re looking for, whether that’s a product, an answer, or a community.
Related ArticlesRelated ProductsUpdated on: 9/21/21

Questions and Comments about this Article

James

I would like to convert the tank fitting to type1 for my propane converted generator. I notice they have different BTU ratings. I have a Predator 3500 watt generator. I saw a 200,000 btu connector. Would this be suitable for me? Thank You Jim

Etrailer Expert
Reply from Les D.

It sounds like you are getting a pigtail where one end fits in your propane electric generator and the Type-1 end connects to your propane tank. 200,000 BTU throughput would be enough for this use. You may need a regulator unless one is built into the generator.

Reply from James

Hi I purchased the dark green type1 connector. I received it yesterday. I had a Pol connector that came with the propane conversion kit. There is a regular that it's connected to. The new dark green connector. IT WORKS GREAT!

Etrailer Expert
Reply from Les D.

@James Glad it worked out so good.

Norman K.

Clear and understadable. Well-written and informative. I will print and laminate. BTW, is there a way to fill my onboard RV tank? RV is stationary and propane company will not come and fill it. Lastly, if I opt for the company's pig and locate it next to the RV, how can I also run a 100' line to my travel trailer (has the two twenty pound tank setup.) Thanks

Etrailer Expert
Reply from Les D.

Mobile propane trucks will generally not fill 20-pound tanks. I have two 20-pound tanks on my travel trailer, and the local refill station makes me take them off the trailer before filling them. You won't find 100 foot rubber propane hoses because you are not suppose to use them full time. For that length run you will need the gas company to run an underground hard-line for you. You could get a 100 pound tank so you don't have to refill as often, but it is cumbersome to take to the refill station.

Reply from Norman K.

@LesD Thanks got the 100# and I ran gas pipe at my home so we'll see.



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