Dedicated AC line - Contractor wants to use BX instead of romex


I’m having a dedicated in wall AC cable run, about 40-50 ft. I was planning on using VH audio cryo’d 10-2 Romex but the contractor wants to use BX since it’s an urban area and more impervious to mice, etc.

Any thoughts on this?

Also I was planning on wiring the end of the run with an 20 Amp IEC connector so I could plug it directly into my Niagara 7000. I don’t know if they will wire it this way but I thought I could always do that myself later.
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Ask him how much extra to run your 10/2 in FMC (flexible conduit). 
Your contractor is nuts. You want the cryo wire. You do not want it in conduit. You are willing to come string it through the holes in the middle of the night if that is what it takes. Etc, etc.


Do what VH says. The contractor knows nothing about audio. And they typically cut corners. Lazy dudes.


 You are the guy who pays the money, you decide. If he refuses, get another contractor.
I'm not certain, but some codes need bx cable ran for the circuits. I know we used romex everywhere unless we had to use bx and even mc cable. We wouldn't have if we weren't forced to by code. Maybe that is what your electrician is talking about.
Your contractor is better off turning down the job.
+1@ cissado.

Licensed electricians are bound to the local codes. As far as cutting corners, the code takes care of that too. So that is just plainly wrong. I was in the business for 40+ yrs so I KNOW what I speak of.
What does this have to do with mice?
Contractor said that mice or rats can eat through romex, which didn't concern me.    I'll have to find out what local NYC code is.


So mice eat in-wall Romex. So says the “code”. So no Romex for in-wall. Because against “code”. I honestly had no idea. I learn new things every day
If you're in a converted industrial building or similar it might be code. It might also be the contractor has run into that problem in your area. If possible it would make no difference if your special wire was run in flexible  conduit if the contractor agrees. 
Thanks for all the replies so far (except that nasty one).   In doing some research it seems BX (named for the Bronx, where it was invented) is required in buildings like mine (over 3 stories).

So any suggestions on a particular metal clad cable to use?  (Steel or aluminum?).  I know there is an oversize neutral cable but the increased diameter would be to hard to work with in my situation (requires some 90 degree bends.    I imagine someone might cryo BX?  

Why I ALWAYS choose BX over Non-Metallic (NM) cable: A real-world example.

Sometimes individual conductors run inside conduit is the only option, but when I have a choice between NM cable and BX, I always choose BX as a residential wiring best practice. There are two main reasons:

1)   BX shields electric fields. Many of my concerned clients have spent a lot of effort and money to shield against and reduce their exposure to electric fields. Some even go as far to turn off the circuits to their bedrooms when they sleep to reduce their exposure. If construction, remodels and renovations are done with BX, the electric field exposure is significantly reduced. The cost is greater, but for a 250-foot roll of BX, it is only about $30 more expensive than NM cable. So for a small job, the extra cost may only be $100 or so, and even for a large job the extra cost should not exceed $1,000.

Source: https://healthybuildingscience.com/2013/01/15/residential-wiring-best/#:~:text=2)%20BX%3A%20BX%20is%....

millercarbon8,881 posts04-24-2021 3:51pmYour contractor is nuts. You want the cryo wire. You do not want it in conduit. You are willing to come string it through the holes in the middle of the night if that is what it takes. Etc, etc.
It could actually be that the contractor wants to stay in good graces with the local code enforcement dept. Ever think of that little detail? Just because someone is willing pay to violate local codes to prevent a potential building fire, doesn't mean a contractor should do it. 

johnspain
25 posts
04-24-2021 8:53pm

Why I ALWAYS choose BX over Non-Metallic (NM) cable: A real-world example.

Sometimes individual conductors run inside conduit is the only option, but when I have a choice between NM cable and BX, I always choose BX as a residential wiring best practice. There are two main reasons:

1)   BX shields electric fields. Many of my concerned clients have spent a lot of effort and money to shield against and reduce their exposure to electric fields. Some even go as far to turn off the circuits to their bedrooms when they sleep to reduce their exposure. If construction, remodels and renovations are done with BX, the electric field exposure is significantly reduced. The cost is greater, but for a 250-foot roll of BX, it is only about $30 more expensive than NM cable. So for a small job, the extra cost may only be $100 or so, and even for a large job the extra cost should not exceed $1,000.

Source: https://healthybuildingscience.com/2013/01/15/residential-wiring-best/#:~:text=2)%20BX%3A%20BX%20is%....

Bravo for your support of actual science.👏👍
Get the Synergistic Research Romex it’s only $50,000 for 50ft 
@ngiordano seriously? Wow... got nothin’.
I was only joking about the 50k . For starters the best thing if your swapping your panel out is get the panel with the silver plated buss then run a dedicated 20A thats 10/2 or 2 , when I ran my dedicated outlet since I was running 1 I just ran 2 so i have 1 20a for my surge and another for my Subs I have dual subs  so im using both outlets for the subs , overkill I know but , before I did all this I got major sag on the line lights were dimming bad so I knew I needed a dedicated outlet . and the first outlet that has the surge protector on it the second outlet I have a IFI AC purifier in it so all 4 outlets  are being used 
@johnspain:  Thank you for the link.  It explains the differences in language that is easy for a novice to understand. 
Before you get into an argument with your contractor you might want to look up the code in your area for what is required to pass inspection. Example in Chicago area almost all electrical wire must be contained in conduit. If there is no code restriction tell him or her what you want and if they won’t go elsewhere.
If you're going to run a dedicated run for power, I'd suggest investing in a good hospital grade outlet at the very least (superior clamping force on the contact area of the plug's pins).

I bought a Puritan PSM156 power cleanser, with close to 1KW of power amp, linear power supply and other items connected, I get no loss in dynamics using it. Thanks to Agon user who put me onto it. Oh, and it was one of the less expensive solutions.



Everything has pros & cons.  Romex and you are stuck with what you installed without opening up the walls.  BX & you have the same.  Use 3/4" flex and there is room to pull more wire through any time in the future.  Even a sub panel.  Almost future proof.  

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Look at page 16. Read pages 31 thru 36.
https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf



I would argue many should read all of this ... about 15 times!  Maybe something will sink it. Worst case, they may give more though to their purchases.


One thing from this presentation is why lots of separate runs are a bad idea as they likely also have separate runs for the ground. That is a good way to induce more voltage difference between grounds. Do a heavy gauge run to a small sub-panel and plug everything in there.





One thing from this presentation is why lots of separate runs are a bad idea as they likely also have separate runs for the ground. That is a good way to induce more voltage difference between grounds. Do a heavy gauge run to a small sub-panel and plug everything in there.

If best wiring methods practices are followed induced voltage onto the EGC (Equipment Grounding Conductor) will not be an issue.

https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf

Look at the picture on page 35. You will see at the top of the picture the worst wiring method used for an induced voltage on the EGC from the hot and neutral current carrying conductors is single conductors pulled loosely, randomly, in a conduit. I would add worst yet is more than one branch circuit installed in a common conduit. A true dedicated branch circuit should not share a raceway, cable, or conduit, with any other branch circuits.

Not only an induced voltage onto the EGC but any noise on the circuit(s) will be transferred to the EGC as well. Therein the noise will be introduced on the chassis of the audio equipment and to the Audio Circuit Signal Ground of the equipment. Kind of defeats the purpose/reason to feed audio equipment like digital and analog from their own dedicated branch circuits.

Back to the picture shown on page 35.
Note the best wiring method is to twist the hot and neutral current carrying conductors together before pulling them in a conduit. The EGC is not part of the twisted assembly. The EGC is just installed along side the twisted pair in the conduit.

Next best wiring method is 2 conductor with ground MC (Metal Clad) cable. The build geometry of the cable is the three conductors are tightly grouped together in a spiral twist.
(DO NOT use 3 conductor with ground or 2 conductor with 2 green insulated grounds, just use 2 conductor with ground.)

Note: MC cable has a lower induced voltage measurement than NM cable, (Romex is a trade name of NM cable.)


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jea48, aluminum or steel clad?
Hello,
My recommendation is put the Romex in a bx shield. Basically do both. You can prevent the mice and have the good cable. This should be legal. 
@ dletch2

https://cdn.cableorganizer.com/old-images/midatlantic/PowerSolutions-middle-atlantic.pdf

MC cable is manufactured in both steel and aluminum. “Steel-Clad MC” cable with insulated ground wire is the best choice for AV systems. It has twisted conductors that help reduce AC magnetic fields, however the steel jacket is what helps most.

Read pages 6 through 9.

FWIW I have read on audio forums that steel conduit tends to take some of the air out of the music where aluminum does not. Therein why some like to use Romex instead of steel conduit.

Aluminum still gives you some RF shielding from airborne RFI entering the cable. Just install the MC aluminum armor cable like you would install Romex cable. Keep it at least 8" to 12" from existing parallel running branch circuits. Even further from lighting branch circuits that use dimmers and or transformer based LED lights. That includes the switch leg side of the circuit.
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If you have mice what does that say about you? Dirtbag audiophile. 
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Reason million and one to not live in one of those God forsaken over regulated over taxed places.
Considering that pretty much every state has as law the National Electrical Code, what place where laws don’t matter do you live?  Cities often take these things more seriously because fires don't just take out one house, they can take out a whole bunch.
Reason million and one to not live in one of those God forsaken over regulated over taxed places.

oh you mean the places where so many artists live, play, and create the music we listen to? They’re called cities and they’re the engine of a whole lot of culture and progress. I’ve lived in many of them and I love them. 
I live in one of those God forsaken red states and we're up to the most recent NEC.
Well... since I'm a licensed electrician and I'm guessing from your uninformed comments you are not congratulations on knowing the acronym NEC. Only commercial construction and over populated densely packed & infested cities require conduit.  Single family homes that make up 98.4% (I looked up the statistic just for you) of all domestic construction across America do not require soft or hard conduit.  An yes those places where culture and art are sooooo very important but no one actually does anything meaningful or make their own way... but just complain and hold their hand out for "their fair share" is exactly what I am talking about.  We the people means THE INDIVIDUAL not as BoBo says ie: the government.
Only commercial construction and over populated densely packed & infested cities require conduit.
Not in my red state. I was required to run through conduit in one of those areas populated by cows more than people. Single story ranch. You need to quit generalizing. If you are a licensed electrician you should know there are codes where conduit is required for certain applications. 
40 to 50 foot run of BX ,
In Chicago BX could only be used for short runs ( 6 -8 feet )  
the rest had to be conduit .
So to have your cake and eat it to ask your electrician 
if he'll run 3/4 inch greenfield ( flexible conduit )
 for you with your 10/2 romex inside 
with a ground wire or a dedicated grounding rod .


Just make sure to check with your insurance company :-)
The contractor should wire it how you want them to and use your wire as well and i think that running it in conduit is a good idea that is what i did along with two quad outlets installed.
OK good times.  So Op in your situation and zip you do need conduit as same as vair68robert states for his zip BX is really intended for sub 10ft runs though some inspectors may interpret BX as flexible conduit.  As a result the most likely best path forward is to use the hi purity copper in conduit.  Cheers. and sorry for the disruption to the thread, the door was flung wide open and well I couldn't resist.  
I see a lot of references to using 10/2 but for some reason I used 10/3 wire. 
What the differences?
10/2 has 3 wires hot-neutral-ground , 10/3 has 4 wires 2 hot-neutral-ground 
I would not want/use regular AC armor cable, (commonly called BX cable), to feed audio equipment.

If AC must be used spec AC HCF only.

Example of regular and HCF AC cable:
https://www.afcweb.com/cross-reference/comparison-ac-mc-cables/
Look at the diagrams of each shown at the bottom of each.

Example of construction of regular AC cable:
https://www.afcweb.com/ac-hcf-armored-cables/ac-lite-armored-cable/

Example of AC HCF cable:
https://www.afcweb.com/ac-hcf-armored-cables/hcf-90-health-care-facilities-armored-cable/

IF MC (Metal Clad) cable is allowed it is recommended over AC cable for branch circuit wiring to feed audio/video equipment. MC is even recommended over MN (Romex) cable.

AC and MC are not the same.

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As a result the most likely best path forward is to use the hi purity copper in conduit.
It’s just 10-2 with ground NM (Romex) cable that has been sent out and cryoed.
(Not by the manufacturer).
I wonder what the electrical inspector would say about that?

OP said:
I was planning on using VH audio cryo’d 10-2 Romex

CORRECTION:   

jea48 said:
IF MC (Metal Clad) cable is allowed it is recommended over AC cable for branch circuit wiring to feed audio/video equipment. MC is even recommended over MN (Romex) cable.
That should read.

MC is even recommended over NM (Romex) cable.
WOW I am a recently retired electrician (35 years) and what needs to be said here is we need to be careful of your opinions when you don’t have the knowledge. This could be dangerous to life and property. Sometimes the local codes are contrary to what we want for our high end audio. There are reasons for the local amendments to the NEC and these local amendments must be adhered too. I’m not going to try to educate everyone on this site but some of the answers show a lack of understanding to the trade. This is where the danger is. When we choose to ignore this that is where we get in trouble. 
Always remember the NEC is written to prevent electrical fire which are usually catastrophic. 
I love my audio like we all do but not at the cost of life safety. 
Enjoy safely 
Considering that pretty much every state has as law the National Electrical Code, what place where laws don’t matter do you live? Cities often take these things more seriously because fires don't just take out one house, they can take out a whole bunch.
The problem is a lot of cities and townships in the us don't really take it seriously. In my city the inspectors don't even have to be licensed, they go to courses but end up playing golf as they don't have to sit through the whole course. When I installed a new service in my house about 30 years ago, I had a 40 amp breaker on a 20 amp circuit and they passed it. 
The NEC, (National Electrical Code), is bare minimum safety electrical standards/requirements. Nothing in the NEC says you can not exceed the standards/requirements. The NEC on its’ own does not have any legal law enforcement. Law enforcement of the NEC is left to the States, Counties, and Cities by the passing of Laws and Ordinances.

States may adopt all of each NEC edition cycle or amend or delete an entire Article or Section of an Article and rewrite the Section as they see fit. The current edition of the NEC is the 2020. There are States that are still working under the 2008 NEC edition. (The NEC is updated every three years.)

https://www.nfpa.org/NEC/NEC-adoption-and-use/NEC-adoption-maps



"This Code is not intended as a design specification or instruction manual for untrained persons."

Quote from 2017 NEC:

National Electrical Code 90.1 Purpose:

(A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity. This Code is not intended as a design specification or instruction manual for untrained persons.

B) Adequacy. This Code contains provisions considered necessary for safety. Compliance therewith and proper maintenance results in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.

Informational note: Hazards often occur because of overloading of wiring systems by methods or usage not in conformity with this Code. This occurs because initial wiring did not provide for increases in the use of electricity. An initial adequate installation and reasonable provisions for system changes provide for increase in the use of electricity..
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