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If you have spare wire pairs in your cable, you can use them for power as well. If using American wire gauge, this increases the effective AWG by 3 (that is, two 24-gauge pairs are equivalent to one 21-gauge pair). If using metric, it increases effective diameter by 40% (1.4x). Either way, it halves the resistance and the voltage drop, and doubles the current you can carry. Also, you should wire the +/- power on matched pairs just like the signal, especially if you are using AC.

Do any of you recommend either for or against any particular regulated power supplies? I need to operate one 700mA camera outside, and two 300mA cameras inside. One would be nice, but I can split the load between two 1A units if necessary. (One I've seen is Philips PH-62092 "digitally-regulated".)

Interesting! What were your cameras doing to indicate this, and what new brand did you replace the Altronix with? (Is Altronix a mediocre brand?) I assume you also had to replace the cameras because of this, or were you able to fix them?

Thanks for your responses. The Honeywell cameras are all well indoors and away from vents, and have plastic housings mounted to drywall. The Speco is definitely the outdoor type. I'll look into this. However, we also have another set of cameras on a slightly different Altronix 24V AC power supply with no trouble at all. The only difference is that one appears to be on a dedicated circuit, whereas the one in question is shared with a computer and DVR. Both are on a UPS, but both are the "offline" type that switch to and from battery with a relay. Also, is there any inherent advantage or disadvantage to 12V DC versus 24V AC cameras? (Aside from the fact that most pro cameras happen to be 24V AC or dual.)

Actually, the DVR and camera power are both protected by a UPS (APC brand, 900VA). Because of this, I don't suspect a surge, and also because they went out randomly over a period of several months. What kind of voltage regulator would I look for? Would this be inserted between the transformer and the terminal block for the cameras, or should it be the 120V plug-in type? Thanks again.

Hello! I'm having an issue with several cameras going bad recently, after about two years of operation. Three of them are Honeywell HD3VC4HR (color, indoor, mini-dome), but the last one to go is a Speco HT-7815DNV (color/B&W/IR, outdoor, barrel-shape, heated). The Honeywells generally displayed many thin vertical randomly-colored stripes on the entire picture with no video for days before they went totally black. One also blew the fuse for its line. The Speco just went blank, but somehow it will still display momentarily when power is applied to it. I've discovered the 24V AC power supply (Altronix ALTV248) is common to all of these, and there is only one camera left operating on it. I suspected maybe the transformer (magnetic, not electronic) had a fault and was the culprit, but it measures at 25.6 volts, both at the box and at the camera locations. Is it possible there is something transient that I wouldn't catch? Is there any way to attempt to fix these? (I do have some background in electronics, so I'm willing to give it a try.) Both Honeywell and Speco refuse to honor their warranties because end-users are forced to go through the distributor, and we have no idea who that is because the dealer/installer is now out of business. Also, I'm looking for recommendations on replacements. A refurbished Sony mini-dome looks nice (actual Sony brand, not just the CCD) -- anyone have reservations about factory refurbs? If the Speco can't be fixed, what particular things should I be looking for, for an area that has a street light (mercury vapor)? Thanks.