Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Bradford "BJ" James]

Hal Bissinger/COMSYSTEC wrote on Tue, 26 October 2010 19:33

Keep in mind that you can always bump up to 100 or even 200 volts. -Hal

Could you give me details on this? Can a 70v system be "modified" to be bumped up to 100 or 200v to account for cable loss, or is this something that has to be started from scratch?

The current plan is to have 2 runs (1 upstreet/ 1 downstreet) with each run having a max # of 30 speakers, each tapped at 30 watts.
Distances for each run are about 2500'
Each run is to be driven from a channel of a 2x 1200 watt amp (69v).
I've installed larger systems before, but not with runs this long.
I appreciate your help and comments.
Thanks,
BJ

[John Roberts {JR}]

Bradford "BJ" James wrote on Wed, 27 October 2010 08:32

Could you give me details on this? Can a 70v system be "modified" to be bumped up to 100 or 200v to account for cable loss, or is this something that has to be started from scratch? The current plan is to have 2 runs (1 upstreet/ 1 downstreet) with each run having a max # of 30 speakers, each tapped at 30 watts. Distances for each run are about 2500' Each run is to be driven from a channel of a 2x 1200 watt amp (69v). I've installed larger systems before, but not with runs this long. I appreciate your help and comments. Thanks, BJ

100V is standard for use in many export markets so 70V fixed install products often already have a 100V tap.

I have seen installs run  3x 70V transformers together to make 210V output (Daytona racetrack to push audio several miles) , it seems you can make 200V easier by adding one extra output transformer to a unit with both low Z and 100V output taps.  Just wire the extra transformer primary to low ohm tap, and 100V winding in series with the existing 100V output. (Note: this must be a true transformer, a cheaper auto-former will not work for this).

Warning, 200V will sting you pretty good when music is playing, so treat this like the 200V it is.

Also the speaker transformer taps will now be hot (2x voltage is 4x power) you may need to make sure you don't send a lot of low bass to the transformers at higher voltage.  

JR

[Charlie Zureki]

John Roberts  {JR} wrote on Wed, 27 October 2010 09:12

Bradford "BJ" James wrote on Wed, 27 October 2010 08:32 Could you give me details on this? Can a 70v system be "modified" to be bumped up to 100 or 200v to account for cable loss, or is this something that has to be started from scratch? The current plan is to have 2 runs (1 upstreet/ 1 downstreet) with each run having a max # of 30 speakers, each tapped at 30 watts. Distances for each run are about 2500' Each run is to be driven from a channel of a 2x 1200 watt amp (69v). I've installed larger systems before, but not with runs this long. I appreciate your help and comments. Thanks, BJ 100V is standard for use in many export markets so 70V fixed install products often already have a 100V tap. I have seen installs run  3x 70V transformers together to make 210V output (Daytona racetrack to push audio several miles) , it seems you can make 200V easier by adding one extra output transformer to a unit with both low Z and 100V output taps.  Just wire the extra transformer primary to low ohm tap, and 100V winding in series with the existing 100V output. (Note: this must be a true transformer, a cheaper auto-former will not work for this). Warning, 200V will sting you pretty good when music is playing, so treat this like the 200V it is. Also the speaker transformer taps will now be hot (2x voltage is 4x power) you may need to make sure you don't send a lot of low bass to the transformers at higher voltage.   JR

 Hello,

  More than likely you'd have no code inspectors breathing down your neck, but, in Michgan... any voltage over 100v is considered "High voltage" and is subject to a whole slew of code regulations.

  Before you get started I'd suggest you investigate these Codes before you attempt any work.

 Good Luck,
 Hammer

[Hal Bissinger/COMSYSTEC]

Quote:

Hello,   More than likely you'd have no code inspectors breathing down your neck, but, in Michgan... any voltage over 100v is considered "High voltage" and is subject to a whole slew of code regulations.   Before you get started I'd suggest you investigate these Codes before you attempt any work.  Good Luck,  Hammer

Since this is out on the street hanging from poles and lamp posts the NEC doesn't apply. Further, I assume that the poles and lamp posts are municipally or privately owned the only permission you would need to get is from the owners. Of course you still need to observe height clearances over the streets and driveways, you don't want a truck to hook your cable taking everything down for blocks! Normally this is 18 feet. You also need to maintain proper clearance from other voltage carrying conductors (above, below or where you cross them), but if this is the only thing on the lamp posts this is not going to be an issue.

-Hal

[Bradford "BJ" James]

Will 12g UTP suffice for this distance on a 70v system?

I don't think I'll venture into 200v territory for this as it'll probably be 10 or more years if ever, before they would ever need to expand. Good info to know though.
Thanks,
BJ

[Hal Bissinger/COMSYSTEC]

How many speakers and what are the distances between each of them and to the amp? Probably need to see a drawing here if there are taps or branches and not a straight run. Are we assuming 30W transformer taps on all speakers?

-Hal

[Charlie Zureki]

Hal Bissinger/COMSYSTEC wrote on Wed, 27 October 2010 15:31

Quote:  Hello,   More than likely you'd have no code inspectors breathing down your neck, but, in Michgan... any voltage over 100v is considered "High voltage" and is subject to a whole slew of code regulations.   Before you get started I'd suggest you investigate these Codes before you attempt any work.  Good Luck,  Hammer Since this is out on the street hanging from poles and lamp posts the NEC doesn't apply. Further, I assume that the poles and lamp posts are municipally or privately owned the only permission you would need to get is from the owners. Of course you still need to observe height clearances over the streets and driveways, you don't want a truck to hook your cable taking everything down for blocks! Normally this is 18 feet. You also need to maintain proper clearance from other voltage carrying conductors (above, below or where you cross them), but if this is the only thing on the lamp posts this is not going to be an issue. -Hal

 Hello Hal,

 I never mentioned the NEC. That is not what I was referring to.  In the State of Michigan anything over 100 volts needs to be installed by a State Licensed Electrician. I'm guessing that Bradford is not a State Licensed Electrician.  

Also... We do not have (at this time) a specific code Licensing requirement for Low Voltage (less than 100 volts).


 In regards to the height requirement of Cable crossing alleyways, walk paths, driveways and streets, I agree with the general requirement you've listed, but I'd suggest he further consult the Local Codes, as these do vary from Municipality to Municipality, here in Michigan.

 There are other State and local requirements not mentioned here that would also apply to the stringing of cable, such as egress and ingress of a building, Fire stop, when conduit is needed, UV protection of cables, proper grounding of suspended wire & cable, etc...

 Thank You,
 Hammer

   

[Bradford "BJ" James]

Hal Bissinger/COMSYSTEC wrote on Wed, 27 October 2010 22:46

How many speakers and what are the distances between each of them and to the amp? Probably need to see a drawing here if there are taps or branches and not a straight run. Are we assuming 30W transformer taps on all speakers? -Hal

2 straight runs is what I have planned right now.

Run "A"- exits the building and goes about 200' before we hit the first lamp post. There will be 2 speakers mounted on the post, each tapped at 30watts. Then repeat 14 times about every 160'. Total run ~ 2500' `900watt load- off one side of a 2x 1200 amp- straight run.

Run "B" is pretty much the same but won't have the full run completed all at once. I do want the electrician to run the cable for the entire run though, so let's assume the same # of units and taps as run "A"

No branches are planned, which is why I would like to double check this with you. Perhaps I should spec 12g 2 or 3 pair for each run and split the load. My longest run will still be 2500', but less load on each run. Then parallel the runs at the amp. Cable starts to get real expensive and heavy though. If a single run of 12g would do it, that would be preferred.

A reputable electrical contractor will be installing the cable. Everything will be done to code and safety where applicable. All I need to do is provide proper spec's for the cable.

[Charlie Zureki]

Bradford "BJ" James wrote on Thu, 28 October 2010 08:21

Hal Bissinger/COMSYSTEC wrote on Wed, 27 October 2010 22:46 How many speakers and what are the distances between each of them and to the amp? Probably need to see a drawing here if there are taps or branches and not a straight run. Are we assuming 30W transformer taps on all speakers? -Hal 2 straight runs is what I have planned right now. Run "A"- exits the building and goes about 200' before we hit the first lamp post. There will be 2 speakers mounted on the post, each tapped at 30watts. Then repeat 14 times about every 160'. Total run ~ 2500' `900watt load- off one side of a 2x 1200 amp- straight run. Run "B" is pretty much the same but won't have the full run completed all at once. I do want the electrician to run the cable for the entire run though, so let's assume the same # of units and taps as run "A" No branches are planned, which is why I would like to double check this with you. Perhaps I should spec 12g 2 or 3 pair for each run and split the load. My longest run will still be 2500', but less load on each run. Then parallel the runs at the amp. Cable starts to get real expensive and heavy though. If a single run of 12g would do it, that would be preferred. A reputable electrical contractor will be installing the cable. Everything will be done to code and safety where applicable. All I need to do is provide proper spec's for the cable.

 Hello Bradford.

   200ft. to the first lamp post and about 160ft. to each subsequent lamp post?

   Those are long runs, and the tension and weight on the cable and guide wires will be pretty high.

  Good Luck,

  Hammer

[Hal Bissinger/COMSYSTEC]

I never mentioned the NEC. That is not what I was referring to. In the State of Michigan anything over 100 volts needs to be installed by a State Licensed Electrician. I'm guessing that Bradford is not a State Licensed Electrician.

Yes, that's true in most states. What you don't understand is that it is wiring within a structure or building. Now, I'm not going to bet the bank on that statement because I'm not familiar with Michigan but I have never seen any requirement for an EC to hang wire on public or private poles or bury it in the ground.

Those are long runs, and the tension and weight on the cable and guide wires will be pretty high.

That may or may not be a problem depending on what the lamp posts are capable of supporting. You are talking about two speakers and two cables hopefully 180 degrees from each other that will cancel out the tension in the post. When linemen design this kind of stuff all the tensions and loads are considered to minimize lateral loading on the poles. That's why you will see down guys and pole to pole guys in addition to the actual cable. You don't say, but what are the poles made of? Wood, steel, spun aluminum?

-Hal