Letter, Hub Style, Cover: Three Choices in Every Part Number
Most guides to this category explain the type letters and stop, which is why the wrong fitting still turns up on site so often. The letter is only the first of three decisions. The hub style has to match the raceway you are actually running, whether that is EMT from Lumera's EMT fittings range or threaded rigid. The cover is usually a separate line on the order. And on larger conductors, the conductor size itself can rule out a body entirely no matter which letter you picked.
The Type Letter, and Why LL and LR Get Ordered Backwards
The letter describes where the removable opening sits relative to the conduit hubs. An LB puts the cover on the back, so the run turns and exits through the wall behind it. An LL puts it on the left and an LR on the right. A C runs straight through with an access cover in the middle, and a T adds a third hub for a branch.
LL and LR are the two that get ordered wrong, and the reason is worth understanding rather than just being told to double check. The designation is read from one fixed orientation. Once the body is mounted and you walk around to the other side of the wall or approach from the opposite direction, the same fitting reads as its mirror image. Settle the letter from the plan or from where you will actually be standing when you install it, confirm it against the product photo, and order then. A body that has already been threaded onto conduit is not going back.
Hub Style Decides Which Raceway It Fits
This is the decision most product pages skip entirely, and it is the one that determines whether the fitting physically connects to your run.
- Set-screw hubs: clamp onto EMT with a screw, which is the standard connection for thin-wall tubing on interior commercial work
- Threaded hubs: take rigid metal conduit or IMC, screwing directly onto the cut and threaded raceway
- Combination hubs: accept more than one raceway type, which reduces how many separate part numbers a truck has to carry
Ordering a threaded body for an EMT run, or the reverse, is a wasted trip rather than a fixable problem. Check the hub description on the listing, not just the letter and the size.
Where the run is rigid or IMC, or transitions between raceway types partway along, the electrical fittings collection covers the broader range of connectors for those systems.
Covers Are a Separate Line on the Order
Conduit bodies generally ship without a cover, and the cover and its gasket are what actually close and seal the fitting. Two things trip people up. The cover is ordered to the body's series and opening rather than to the conduit trade size, so matching the number on the box to the conduit you are running is not a reliable method. And covers are not interchangeable between manufacturers or between depth series within the same manufacturer, because the opening profile and the gasket seat differ.
The practical rule is to order the cover against the body's part number, and to order spares, because a missing cover holds up an inspection over a part worth very little. Lumera's box covers and rings collection carries covers alongside the other enclosure closures.
Conductor Size Can Rule a Body Out Completely
This is the point that catches people on feeder and service work, and almost no retail page mentions it.
Where conductors 4 AWG and larger are being pulled, the code sets a minimum distance from the raceway entry to the opposite wall of the fitting, based on a multiple of the trade size of the largest raceway. A standard conduit body in the common sizes generally does not meet that dimension. It is not a matter of being careful with the pull; the fitting is simply not permitted as a pull point for conductors that size unless it is specifically sized and marked to comply.
Two ways out. A mogul body is an oversized version with substantially more internal depth, and deeper form series give more bending room within the same opening, which is what those form numbers on the part are describing. Or the pull point becomes a proper box instead, which is often cheaper and simpler at feeder scale. The sizes available for that are in Lumera's junction boxes and enclosures collection.
Splices Are Allowed, But Only Under One Condition
A conduit body may contain splices, taps, or devices only if the manufacturer has durably marked it with its volume in cubic inches. If there is no volume marking, the fitting is a pull point and nothing else, and putting wire nuts in it is a violation regardless of whether anything is physically pinched.
Where the body is marked, the splices still have to fit inside a proper fill calculation covering conductors, devices, and clamps. In practice, the small bodies people most often want to splice in are exactly the ones with the least room, and a half inch fitting stuffed with connectors is one of the most common quiet code violations in the trade. It usually passes unremarked and it is still wrong.
The 360 Degree Budget Is Why You Place Them
Conduit bodies are often thought of as corner fittings. The more useful way to see them is as the thing that resets a limit. Code caps the total bend between pull points at the equivalent of four quarter bends, and once a run has used that up, a pull point has to be introduced before any more turns are added.
Planning that budget before bending anything is what stops a run from being unpullable at the end. Count the degrees along the intended path, place a body where the count is about to be exceeded, and confirm that the cover will end up somewhere a person can actually reach.
Material, Weather, and Drainage
Aluminum is the general-purpose choice and what most of this collection is built around, light to handle and corrosion-resistant for typical interior and exterior work. Malleable iron takes physical abuse better and belongs in industrial areas where a fitting might get struck. PVC bodies solvent-weld into PVC raceway for buried and chemically aggressive runs.
Outdoors, the gasket does the sealing and the fitting needs to be listed for the location. Orientation matters too, since a body positioned so condensation collects against the conductors will corrode from the inside regardless of how well the cover seals. Where drainage is genuinely needed, the code permits small drain openings in bodies listed for damp and wet locations, within a defined size range and following the manufacturer's instructions.
Accessibility, Bonding, and Installation
A conduit body has to stay reachable after the building is finished. Burying one behind stucco, siding, or a sealed ceiling defeats the purpose of installing it and creates a problem for whoever troubleshoots the run later. Fix the elevation and the clearance in front of the cover at layout, not after the raceway is up.
On metal systems the body is part of the equipment grounding path, so hub connections need to be made up tight, and some installations call for bonding hardware at the entries rather than relying on the fitting alone. Lumera's conduit and grounding bushings collection covers that hardware and the bushings that protect conductors at the opening.
Anything connecting to building wiring should be installed by a licensed electrician, who will confirm the fill, the bonding, the support of the raceway either side of the fitting, and that the location suits the environment.
Conduit Body FAQs
What is the difference between an LB, an LL, and an LR?
The letter says where the removable opening sits relative to the hubs. LB puts the cover on the back, which is what lets a run turn and pass through a wall. LL puts it on the left and LR on the right. Read the letter from one fixed orientation, because a mounted body approached from the other side reads as its mirror image.
Will any conduit body fit my conduit?
No. The hub style has to match the raceway. Set-screw hubs clamp onto EMT, threaded hubs take rigid or IMC, and combination hubs accept more than one type. Check the hub description on the listing rather than ordering on the letter and trade size alone.
Do conduit bodies come with covers?
Usually not. The cover and gasket are ordered separately and matched to the body's series and opening, not to the conduit trade size. Covers are also not interchangeable between manufacturers or between depth series, so order against the body's part number and keep spares.
Can I splice wires inside a conduit body?
Only if the manufacturer has durably marked the body with its volume in cubic inches, and only within a proper fill calculation. An unmarked body is a pull point and nothing more. Small fittings packed with wire nuts are a common violation that often passes unnoticed and is still not compliant.
Can I use an LB to pull large feeder conductors?
Generally no. For conductors 4 AWG and larger the code sets a minimum distance from the raceway entry to the opposite wall based on the largest raceway trade size, and standard bodies in common sizes do not meet it. Use a mogul or deeper form body specifically sized for it, or use a proper pull box instead.
How many bends can I put in a run before adding a conduit body?
The limit between pull points is the equivalent of four quarter bends. Count the degrees along the intended route before bending anything, place a body where the count is about to be exceeded, and check that the cover will land somewhere reachable.
