Remote heads too dim

[JohnME]

I just finished an 11,000 sq ft job, and when I went to test the emergency lights, the remote heads were too dim to be of any use. They were fine close to the battery pack, but the further away I got from it, the worse they got. I ran #12 to the remote heads, there are about 10 heads per battery pack, about 100' away is the largest run.

I installed the system per the engineers design. I have my own fix- breaking the problem circuits in half, and installing another pack to pick up the slack.

The city does their certificate of occupancy Monday afternoon, I assume they will fail us for this.

Do I eat the cost of this fix and just do it? Should I just shrug it off and see what the city says?

Thanks for any input.

 

[JJWalecka]

"I ran #12 to the remote heads, there are about 10 heads per battery pack, about 100' away is the largest run."

I thought I read something about 10 AWG had to be used for remote heads. Perhaps I was misinformed.

JJ

 

[cadpoint]

I'm doing a remote head application right now the literature did not say that multiple heads where allowed to be run this way. OK the diagram only showed a exit sign or even a flood use and then a remote head and thats how there installed.

1 ft/candle for 90 minutes (remote output), how do you know that the lamp is not producing this ?

 

[hillbilly1]

You are starting with only 12 volts, if its like most systems, you are experiencing extreme voltage drop. the old Sams Clubs I used to do called for a minimum #8 to the heads. You will have to upsize your wire to compensate.

 

[JohnME]

Thanks guys. The plans show #12 run to the remote heads. I know they are to dim because if I shut the lights off at night, I cant see anything.

If there's a reference to using #10 wire for these heads in the NEC I would love to get ahold of it. I knew this was going to be an issue, I just chose to ignore it because I had too many other items on my plate at the moment. Plus, the "engineer" is horrible with the design.

 

[augie47]

do you have 1 set of #12's to all 10 heads, or one set per head ?

 

[whillis]

You installed the lights per the engineered drawings so I don't see any reason why you should eat the cost of making it right.

 

[JohnME]

1 set of #12, all lights in parallel. The GC is all worked up over this, change order here we come.

 

[cadpoint]

OK, so will everyone be embrassed when the EE comes out with their light meter ?

 

[stickboy1375]

1 set of #12, all lights in parallel. The GC is all worked up over this, change order here we come.

no wonder why they are dim. Just for ha,ha's did you check the voltage at the last light?

 

[augie47]

definitely part of the problem. if you check you probably have 5 watt to 10 watt lamps, 6 or 12 v system, so you may be loading the #12 to or beyond its ampactity. as stickboy notes, your voltage drop is undoubtably beyond significant.
a set of #12's to each head might have been more in order.

 

[LarryFine]

One quick test: how's the brightness of the main heads?

 

[quogueelectric]

You should get paid if your plans showed 12wire.

 

[JohnME]

The main heads are fine, and as we go further down the circuit things get dim.

I dont understand cadpoint- I am telling you that they are so dim that it doesnt even light up a dark 10x10 room, I cant see anything, not even the door handle.

 

[LarryFine]

The main heads are fine, and as we go further down the circuit things get dim.

That's voltage drop, all right. Upping the conductor size is the only cure, unless you run additional conductors and separate the heads into groups of 2 or 3.

You really should use the head currents to calculate voltage drops, as you should with any loads.

 

[hillbilly1]

Thanks guys. The plans show #12 run to the remote heads. I know they are to dim because if I shut the lights off at night, I cant see anything.

If there's a reference to using #10 wire for these heads in the NEC I would love to get ahold of it. I knew this was going to be an issue, I just chose to ignore it because I had too many other items on my plate at the moment. Plus, the "engineer" is horrible with the design.

You will find no reference in the NEC about using # 10, unless you are exceeding the ampacity of the wire, which is possible. Just to make it easy, Let's say your system is 12 volts, each head is 24 watts, that's 2 amps per head. This adds up quickly. The 5% total voltage drop at the end use may be a section you can use. The EE may come back saying that you were supposed to run dedicated runs to each head, but I think he just screwed up.

 

[mdshunk]

Could it be as simple as you have 6-volt battery units, and 12 volt remote heads? I've seen that a lot. Could it be as simple as the battery units have not charged yet?

 

[JJWalecka]

JohnME

I am pondering.... that many heads off one battery pack? That?s what the manufacturer specified? Do you have a model number? I would like more info on product chosen.

I have seen a dual head battery pack with the option of adding a single additional head, Thanks.

JJ

 

[hillbilly1]

The older big blue box's uses many of these, they run anywhere from 6-10 heads or more depending on the capacity of the battery/charger unit. Replaced batteries in a court house system that had 4 large batteries that powered all of the emergency lights in the building. With more and more companies opting for back up generators, these are slowly going away. Still prevalent in other countries though, did some consulting work for the orange box in Chile, and they had a room full of batteries for backup in that store.

 

[mdshunk]

...there are about 10 heads per battery pack, about 100' away is the largest run.

...that many heads off one battery pack? That?s what the manufacturer specified? Do you have a model number? I would like more info on product chosen.

There are certainly units that do that many remote heads, and much more, but you've got me thinking now JJ. If someone was foolish enough to run 10 remote heads on an otherwise "ordinary" battery unit, they'd be in duck soup. Unless you order them special, the off the shelf one's won't do but a couple remote heads normally. They often have room to add more batteries inside the cabinet, but then you can often tax the charging board if it's not setup to charge that many batteries.