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!

You can also have our expert Jake walk you through the different types of propane fittings in this helpful video.

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

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
On the Hose Going Into the Regulator
On the Hose Coming Out of the Regulator
On the Supply Hose (Connected to Main Propane Line)
On a Tee Fitting, Grill, Outdoor Kitchen, or Accessory Port
On a Portable Propane Cylinder

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.

Hose Going Into Regulator

Looking 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

Hose Coming Out of Regulator

The 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 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.

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.

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.

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Written by: Amber S.

Updated on: 3/18/2022

Benjamindees

11/27/2023

It's really important to point out that there are (at least) two different flare fittings in common use and that they are INCOMPATIBLE with each other and WILL LEAK due to different flare angles.

Jeremy B.

10/30/2023

Great article. I'm trying to connect a propane generator to a propane auto chaneover. Problem is, the generator has a propriety quick connect. They provide a hose with a QCC1 female on the other end. I cannot find a 3/8 NPT male to QCC1 adapter anywhere, I suspect it doesn't exist. So how to do I make this happen? Wil a 3/8 Flare fit?

Jonny B.

7/23/2023

I'm looking the extend my pigtails coming off my dual tank regulator to my dual tanks because they are too short. The tension created from bending them to properly fit the two propane tanks causes the hoses to leak at the point where the rubber hose meets the fitting. According to this guide, it looks like my pigtails need to be type 1 male to male inverted flare and at least 2 feet long, preferably longer. Any products here at etrailer like that?

Mike L.

8/2/2023

@JonnyB How long are your current pigtails? We offer 12 inch all the way up to 12 feet. I'd recommend a braided hose for the sake of durability. You can see what we offer by using the provided link.

Helpful Links

dept-pg-propane_fittings-pt-pigtail_hoses-pc-pol_~_male.aspx

Jonnyb

8/2/2023

@MikeL currently 1 foot. Doesn't matter how tough the hose is if the fittings attached at the end are cheap. I'm looking for the hoses that connect the dual tank regulator to the tanks themselves.

Jonnyb

8/2/2023

And I quite clearly said "at least 2 feet long" idk why I'm even replying. It's like my comment wasn't even read.

See All (6) Replies to Jonny B. ∨

Vic C.

7/20/2023

Is there a o ring in the male screw on connector that attaches to the portable propane tank?

Mike L.

8/2/2023

@VicC Which exact fitting? Are you talking a 20 # tank?

Trevor

7/1/2023

I have a propane leak on the connector labeled 30 PSIG. Does anyone know what that is called? I've looked online to find it and am having no luck. This is on the second propane tank on one side of our 5th wheel.

Heather A.

7/17/2023

@Trevor 30 PSIG is just the pressure measurement so I can't identify what you need by that description. Can you send me a photo of the connector you are trying to replace? I am happy to help.