Old Fire Truck Lights

[jmellc]

My church is getting a piece of an old fire truck with spotlights. Was a 1969 model. I am sure these would be 12 volts, right? I need to assemble a 12 volt power supply and rectifier to convert to D.C., then use a relay and on/off timer if they want the 2 lights to alternate?

 

[gar]

170404-1653 EDT

By the late 1950s US autos were 12 V. With the availability of high current silicon diodes alternators replaced generators. By 1957 car radios were starting to become transistorized.

Find out the bulb part number and check its specifications for voltage and current.

Why convert AC to DC?

.

 

[zbang]

Find out the bulb part number and check its specifications for voltage and current.

Definitely, some trucks were/are 24v.

 

[Frank DuVal]

I thought you said "Old Firetruck". This is modern. Old fire truck could have acetylene lights!

Light bulbs run on AC fine, like in your house.

On many vehicle lighting situations, you can change the bulb to whatever voltage you can make easily.

Do check current specifications on these lamps. If headlamps or spotlights, can be much higher than you think.

 

[jmellc]

If I keep it AC, can I still use 1 power wire and chassis ground for each lamp? I assume that works ok with AC?

 

[kwired]

My church is getting a piece of an old fire truck with spotlights. Was a 1969 model. I am sure these would be 12 volts, right? I need to assemble a 12 volt power supply and rectifier to convert to D.C., then use a relay and on/off timer if they want the 2 lights to alternate?

Depends. If they are large area lights they very well may run off 120 VAC from an on board generator. A smaller spot light that is operated from driver's seat is likely run off vehicle's DC system but could be 12 or 24 volts.

As mentioned a 12 or 24 volt lamp will work on AC or DC.

 

[ActionDave]

If I keep it AC, can I still use 1 power wire and chassis ground for each lamp? I assume that works ok with AC?

Yes, that will work.

 

[growler]

My church is getting a piece of an old fire truck with spotlights. Was a 1969 model. I am sure these would be 12 volts, right? I need to assemble a 12 volt power supply and rectifier to convert to D.C., then use a relay and on/off timer if they want the 2 lights to alternate?

What do they plan on doing with this truck? A 1969 model is not that old and it would probably be easy enough to get a manual for it.

 

[big john]

What do they plan on doing with this truck?

It's a pumper truck for large group baptismals.

 

[ggunn]

Yes, that will work.

What? Run AC hot to the lamps and use the body of the truck for a neutral? That doesn't sound safe to me.

 

[ActionDave]

What? Run AC hot to the lamps and use the body of the truck for a neutral? That doesn't sound safe to me.

At 12V or 24V.

 

[ggunn]

At 12V or 24V.

I see. Still, is this permitted by the NEC? I don't know from low voltage AC.

 

[growler]

What? Run AC hot to the lamps and use the body of the truck for a neutral? That doesn't sound safe to me.

I see. Still, is this permitted by the NEC? I don't know from low voltage AC.

As an automotive vehicle it' not even covered by the NEC, Atricle 90.2 (B)(1).

That's why I asked what they intend to do with the vehicle. If it's not tagged as a vehicle then it could be considered a stucture ( some sort of signage, maybe). Here you can't even keep a vehicle unless it's tagged and insured.

 

[kwired]

My church is getting a piece of an old fire truck with spotlights.

I believe they are just using spotlights that once were on a vehicle (add: maybe some more then just the spotlights, certainly not the entire vehicle)in the church somewhere, NEC should apply.

Now enter the problem presented by 410.6 and whether these luminaires are listed.

 

[Frank DuVal]

Once you use a transformer to derive the 12 or 24 VAC, no reference to ground of either transformer output lead or other issues to contend with. This is not permanent wiring inside walls, right? This becomes a portable lamp that plugs in to a receptacle (put plug on transformer cord).

However, since water is involved in this action of using the lights, I would connect the metal surfaces of the lights to ground via a three wire cord/plug on the transformer.

Now if this is a permanent installation of a stationary truck, then bonding of the metal truck/lamp shells is mandatory. The low voltage still does not need to be ground referenced.

 

[cowboyjwc]

Why not just use a low voltage lighting time clock or transformer? I did this the other way for some out door lighting. We changed the 110v fixtures into 24v fixtures with a LV lighting supply and 24V bulbs.

 

[kwired]

Once you use a transformer to derive the 12 or 24 VAC, no reference to ground of either transformer output lead or other issues to contend with. This is not permanent wiring inside walls, right? This becomes a portable lamp that plugs in to a receptacle (put plug on transformer cord).

However, since water is involved in this action of using the lights, I would connect the metal surfaces of the lights to ground via a three wire cord/plug on the transformer.

Now if this is a permanent installation of a stationary truck, then bonding of the metal truck/lamp shells is mandatory. The low voltage still does not need to be ground referenced.

I don't think the entire truck is being used just a portion that contains the lights in question. Also water involvement? - I think you got that from the large group baptismal comment that I believe was intended as a joke. It certainly did not come from the OP anyway.

 

[jmellc]

I got it working. I ran hot and ground to the 2 spotlights, as I could not get a good reading up to that part of the frame. Ifed them from 1 12 volt/50 watt transformer and used another trx for the tail lights. I ran only hots to them. I put an 8x8 junction box on the back of the truck and put the trxs in them. Grounded 1 side of the tail light txf to the frame and installed a cord and plug. Works well.

Now I need to find a blinker switch of some type for the tail lights.

 

[gar]

170412-0939

jmellc:

Check the load current on your transformer secondary, and see if you are overloading the transformer.

I wouldn't call your secondary leads hot and neutral. Chassis or common, but not neutral, for the lead to the truck frame. Hot is possibly ok, but 12 V AC might be better.

Doing a quick search for headlamp power seems to imply up to possibly 70 W per bulb.

.

 

[ggunn]

I got it working. I ran hot and ground to the 2 spotlights, as I could not get a good reading up to that part of the frame. Ifed them from 1 12 volt/50 watt transformer and used another trx for the tail lights. I ran only hots to them. I put an 8x8 junction box on the back of the truck and put the trxs in them. Grounded 1 side of the tail light txf to the frame and installed a cord and plug. Works well.

Now I need to find a blinker switch of some type for the tail lights.

I don't know if standard 12VDC flashers will work for 12VAC, but they are cheap so it'd be worth a try.