By Kent · Lock Depot Staff Writer

Camera power is not door power

Most of what Altronix sells us runs locks: 12 or 24 volt DC, battery backup, a fire alarm tie-in. The ALTV line is a different animal. These are CCTV camera power supplies, and the first thing to settle is whether your cameras want AC or DC. Plenty of older commercial dome and PTZ cameras run on 24VAC. Newer boxes and bullets often run on 12VDC. Buy the wrong type and nothing is damaged, but nothing runs either.

Three models cover most jobs we see: the ALTV248, the ALTV244175UL and the ALTV1224DC. Here is how to choose.

Step one: AC or DC

Read the label on the camera or its power brick. If it says 24VAC or 28VAC, you want the first two. If it says 12VDC or 24VDC, you want the third. All three are wall mount supplies with fuse protected outputs and a lifetime manufacturer warranty. What changes is what comes out of the terminals.

One note that matters on a multi-camera system: every ALTV listing says the unit maintains camera synchronization. On a set of AC cameras fed from one supply, switching between them on a monitor does not roll the picture. Split the cameras across unrelated supplies and you can lose that. Keep a group of AC cameras on one supply when you can.

ALTV248: eight outputs, selectable AC

The ALTV248 is the general purpose one. Per the listing:

• Output: 24VAC or 28VAC, selectable.
• Current: 4 amp at 24VAC, or 3.5 amp at 28VAC (100VA).
• Outputs: eight, each fuse protected. Output fuses are rated 3.5 amp.
• Input: 115VAC, 50/60 Hz, 0.9 amp.
• Extras: surge suppression, an AC power LED and an on/off switch.
• Size: 8.5 in. high, 7.5 in. wide, 3.5 in. deep, with 1/2 in. and 3/4 in. combination knockouts.

Eight fused outputs let you run eight separate camera feeds from one box, and a shorted cable blows one fuse instead of dropping the whole system. That is the real benefit of a fused board over a single transformer with a daisy chain of wire nuts.

One honest caveat. The listing for this model does not state a UL listing. Its sibling, the ALTV248UL, has the same eight output layout, is listed UL and CUL for commercial CCTV equipment (UL2044), and carries a lower rating of 3.5 amp at 24VAC (85VA). If an inspector or an insurance requirement calls for a listed supply, that is the one to look at. Our Altronix LPS3C24X power supply article covers it, and also explains why a 24VAC camera supply will not run a DC maglock.

ALTV244175UL: fewer outputs, a lot more current

The ALTV244175UL trades outputs for muscle:

• Output: 24VAC or 28VAC, selectable.
• Current: 7 amp at 24VAC, or 6.25 amp at 28VAC (175VA).
• Outputs: four, each fuse protected, 3.5 amp fuses.
• Input: 115VAC, 50/60 Hz, 2.7 amp.
• Protection: surge suppression and an illuminated power disconnect circuit breaker with manual reset.
• Listing: UL and CUL listed.
• Size: 12.25 in. high, 7.25 in. wide, 4.5 in. deep.

Four outputs at 3.5 amp each is 14 amp of fuse capacity, but the supply itself delivers 7 amp at 24VAC. So the fuses are not the limit. The transformer is. This model is for a few heavy loads: a pan-tilt-zoom camera with a heater and blower, for example. Cameras with heaters pull far more current than the camera alone. The circuit breaker on the front is handy in the field. When something trips, you reset it with a finger instead of hunting for a fuse in a ceiling.

ALTV1224DC: the DC choice

The ALTV1224DC is the one to buy when the cameras run on DC. Per the listing:

• Output: 12VDC or 24VDC.
• Current: 4 amp total continuous.
• Outputs: eight, fuse protected, with 1 amp output fuses.
• Regulation: filtered and electronically regulated.
• Input: 115VAC, 50/60 Hz, 1.45 amp, with 3.5 amp input fuses.
• Extras: surge suppression, an AC/DC power LED and an on/off switch.
• Size: 13.5 in. high, 13 in. wide, 3.25 in. deep.

The fuse rating is the thing to check. Each output is fused at 1 amp, so one camera on one output cannot draw more than that. A standard IP bullet camera is fine. A camera with an IR illuminator and a heater may not be. Read the camera's current draw in its spec sheet before assuming one output will do.

It is also a physically larger box than the AC units. Allow for the 13.5 by 13 inch footprint when you pick a wall spot.

Totalling the load

Add up the current of every camera you will hang on the supply, then leave headroom. A common rule of thumb in the trade is to stay under about 80 percent of the rated output, so that a hot closet and a long run do not push the supply to its edge. The catalog lists the ratings. It does not give a derating figure, so treat the 80 percent as our field habit, not a manufacturer number.

Then check cable length. Low voltage drops quickly over a long run of thin wire, and a camera at the far end of a parking lot may see well under its rated voltage. Use heavier wire for the long ones and keep the supply near the group it feeds.

If cameras and a door lock share a closet, give them separate supplies. A camera supply is built for steady video loads. A lock coil is a different kind of load, and mixing them is how a monitor starts flickering every time somebody opens the door.

Quick pick

1. Cameras say 24VAC, up to eight of them, light loads: ALTV248.
2. Cameras say 24VAC, a few heavy ones with heaters: ALTV244175UL.
3. Cameras say 12VDC or 24VDC: ALTV1224DC.
4. A listed supply is required: the ALTV244175UL or the ALTV248UL, not the ALTV248.

Common questions

Can I power a DC camera from an AC supply?

No. The ALTV248 and ALTV244175UL put out AC. A DC camera needs the ALTV1224DC or another DC supply.

How many cameras can the ALTV248 run?

Up to eight, one per output, as long as the total stays inside the 4 amp at 24VAC rating.

Does the ALTV1224DC have battery backup?

The listing does not mention a battery charger or backup. Plan for a separate UPS if you need the cameras to ride out an outage.

Can I switch between 24VAC and 28VAC?

Yes on the ALTV248 and ALTV244175UL. The listing calls both selectable.

Where does the supply mount?

On the wall, with 1/2 in. and 3/4 in. knockouts for conduit.

Browse the full line on our Altronix page. If you are also feeding access control from the same closet, our Altronix ACM8CB, PD4UL and MOM5 article covers the distribution side. Send us the camera model and how many you are hanging, and we will tell you which supply fits.