Type of conduit for circulators?

dgoldstein

What type of conduit it is recommended for using with circulators that are installed in a conditioned space?

Mine are currently run with a blue plastic, rigid corrugated tubing - it's a bit of a PITA to manage (was done by previous owner) and am wondering what other acceptable options are out there to tidy up and streamline the wiring.

Any insight or examples appreciated!

SWEI

What you are describing is called Electrical Nonmetallic Tubing, or ENT. It is not approved for use where exposed to risk of damage, which how most inspectors would interpret an installation in a boiler room.

The proper way to do this is using flaxible metal conduit, Metal-Clad (MC) Cable or liquidtight flexible conduit (LFNC or LFMC.)

MC Cable (we used to call it BX) is an armored cable assembly that looks like a slightly skinnier version of 3/8" flexible metal conduit. The slightly tricky part is that the vast majority of suppliers stock MC cable in 12ga solid, and you really want 14ga stranded for small pumps. Another option is to buy a bit of 3/8" flexible metal conduit and pull your own wires in, or buy a "fixture whip" which is a pre-cut length with ends and wire already in it. They typically come with 18ga or 16ga wire.

delta T

I have always run 3/8 flex metalic conduit and pulled my own wires. if you do this remember to use the little red plastic inserts on both ends to protect the wire from getting nicked from the sharp end of the conduit. easy to make it look good, protects the wire, and is easy to manage after the fact.

dgoldstein

Is this the type of stuff you guys are referring to?

https://www.homedepot.com/p/Southwire-14-2-x-250-ft-Stranded-CU-MC-Metal-Clad-Armorlite-Cable-55017701/202250323

dgoldstein

I did also see the finished whips and do understand that I'd be wise to swap out the solid wiring to the 14ga stranded.

thanks folks!

JUGHNE

14 gauge solid copper can be a bit tough making connections inside of some pumps and controls.
I use the 3/8" flex, fittings with the bushings and 14 stranded, sometimes 16 stranded, depending upon the load.
Also then with the stranded crimp on the forks or rings as needed. Small orange wirenuts for pump connections.

ratio

That roll says stranded, it'd be Just About Perfect. You'd want to make sure that either the individual pump outputs are (internal to the boiler) fused at less than 15A, or the whole assembly is on a 15A circuit breaker.

I can't recommend enough the right tool for working with BX/AC/AP cable.

HVACNUT

> @ratio said:
> I can't recommend enough the right tool for working with BX/AC/AP cable.

When I first started, I always got ribbed for using a Rotosplit by the electricians. Real men use a hacksaw.

Tinman

Smart men use a small, portable band saw. Quickest, cleanest cut you'll ever get.

the_donut

Pipe cutter for outer and wire cutter for inner for me. Pretty much same as cast.

JUGHNE

Yes, it says stranded. None of my suppliers stock it so l jumped to conclusions.

Stephen, you use a band saw to remove the outer cladding?

Hilly

I got a BX cutter. It's a gem of a tool for pretty cheap too. I don't care what any electrician says... It's a non brainer for me. I love it.

Gordy

+1 on the BX cutters they are sweet. Plus you can use it on preloaded BX.

Tinman

@JUGHNE - I should have clarified. I don't use bx at all. I was referring to greenfield. Most of the inspectors near me require the ability to pull wire through whatever pipe you use. Chicago area is tough.

ratio

I was feeding layins down a hall one afternoon, some years ago, merrily roto-splitting the feeders & popping them into the lights. On the third one, BANG!

I had been stripping them hot. I didn't realize it until I accidentally touched the hot to the connector. After that, I was sold on the roto split.

EBEBRATT-Ed

Hacksaw for me, never used a rotosplitter. I would stay away from solid wire. The "armorlite" with stranded wire looks good to me.

Most inspectors don't enforce it but I think there are restrictions on using Greenfield smaller than 1/2" I will have to look it up.

I have limited room in my truck so If I have my way I usually only carry 1/2" greenfield and fittings but that's just me. Metallic sealtight is the best but $$$. Like the non-metallic sealtight but don't like the fittings and that stuff is hard to pull wire through

@delta T red head insulators are fine but not code required on greenfield only MC & BX

JUGHNE

There might be a 6' NEC code limit on the length of 3/8" FMC.
Did you ever come across 3/8 FMT? Flexible metallic tubing.
Very bendable, haven't seen it for years
1/2" seems over the top to me. Bigger than the pump or control it goes to.
My AHJ would only inspect the power supply to the unit.
He sort of considers anything for controls/pumps to be part of the unit. Is usually happy unless you throw Romex around.

EBEBRATT-Ed

Think the 6' limit applies to all sizes of flex. Never saw the FMT. I have seen the "extra flexible" FMC. I just carry 1/2" cause after 3-4 wires 3/8" is too small. Can get a couple #8s & a #10 ground in 1/2" in a pinch. And I'm used to using the 1/2" can't bend it as tight but I plan for that so it comes out ok. Hate fighting to get wires in small stuff.I have so much stuff in my truck electrical stuff is pretty limited. I usually buy what I need.

Sadly, I am up for code updates this year...a bunch of them.....total of 4 I think. Gonna drop some licenses soon when I retire

dgoldstein

this is what's on my system...

Zman

Your install is a little to 3D for my liking. What's with the PEX coming straight at you?
In your case, being a non wet location, I would use 3/8" flex MC . Put a 90 transition on the circ and strap it to the wall.

dgoldstein

Yeah, the blue stuff is a PITA to work around when checking the pipes and/or occasionally actuating the valves.

The red PEX coming straight out goes is a return from that utility room zone. I never turn it on since the ambient heat from the boiler, hot water heater, and exposed copper keeps the room above 65* year round.

The red PEX coming in from the side wall and from the ceiling are the returns from my first-floor zone (most frequently used) and my upstairs (seldom ever active).

This is a complete picture of the heating piping around the boiler for my three zones...

JUGHNE

"Smurff" tube (the color gives it away).

Ed; from the 2014 NEC, (I'm too cheap to get the 2017 book).

MC cable, 320.12.....Uses not permitted include:
(1) where subject to physical damage???
{My AHJ says it is to be protected like Romex, in his opinion being 6.5' above the floor or stapled to a running board, we don't agree with it but it is his call. So we use FMC, usually 3/8"}

ENT, 362.12 (Smurff tube) pretty well the same restrictions but include exposure to sunlight.

FMC, Flexible Metal Conduit seems to have the "Where subject to physical damage" clause..........who defines physical damage?
The 6' rule is unclear. We used to run 1/2" FMC (Greenfield) to wire complete apartments buildings.

So all is subject to the interpretations of the AHJ.
I simply strive to keep him happy, with-in reason, without arguments.

For the OP/HO I would do the MC or 3/8" FMC.
Will they sell you cuts of the MC, 250' is a lot to get rid of.

Your installation picture makes it obvious that there may not have been a permit/inspection, (if required) for you job.

dgoldstein

The previous owner was an HVAC contractor by trade. I'm sure he just did it himself, submitted the prints and didn't have a thorough inspection.

I'll eventually clean it up, maybe once a circ goes dead or a decision to change the circ configuration. I'm discussing in another thread the merits of going to a single pump with zone valves.

EBEBRATT-Ed

@JUGHNE , don't think a supply house will cut a 250 of MC but of course it's available in shorties at big box.

Just got my 2017 code book today via amazon. Around here u can't get into the code update class without one (sigh)

I guess there trying to squeeze more into it without making it bigger.

The print is so small I can't even see it. I have already put it down in disgust

Solid_Fuel_Man

I always use a roto-split we call it "the can opener"! Most other electricians just break and cut clean with dikes. I've seen that little burr cut into the wires enough to never break it open. Although nor code required I also always use the red "never shorts" as we call them. I go through many feet of 3/8 flex in the course of a year, 6 feet is the length limit, but never enforced here.

JUGHNE

I think most of the changes-"upgrades" are in the residential area. But a big change in GFCI requirements for outlets, such as welders etc. Painful.

Solid_Fuel_Man

Some of the resi stuff was relaxed, but much of the arc-fault stuff is way overdone. The 3 year code cycle needs to be eliminated IMO. A bit too much job justification but I'm not going to derail!

JUGHNE

The 2020 version is in the making as we speak.