Is it possible to run a Federal STL-10 or STH-10 on 120V

[Tboltguy]

Hey everyone,

I was considering getting a Federal STH-10 or an STL-10 from WSS this summer, and I was wondering if it is safe/possible to run one on 120V.

Thanks in advance, Milo

[uncommonsense]

Absolutely not. Its possible if you want to burn your house down from an electrical fire. The draw would be far too much for 120V to handle.

[OHIO Desperado]

Absolutely not. Its possible if you want to burn your house down from an electrical fire. The draw would be far too much for 120V to handle.

You SURE about that?
An STH/L-10 is fused at 50 amp at 240 volts.
So the the current draw from the same load and half the voltage would be half the current.
So 25 amps. Mind you a 15 amp breaker which is typical for a run of the mill outlet would pop almost immediately.
But a 20 amp or 30 amp breaker, fed with the correct wire, would probably hold and run the motor up to not quite half speed.

That being said, if you would need to run a new circuit, why not install a CORRECT circuit with a proper 50 amp outlet and a manual disconnect (could use a 50 amp welding outlet)
and just be done with it.

But as far as burning down the house,,,, only if the wiring in the house was improper, the fuse / circuit breaker was improper would you chance a house fire over the attempt.
If everything was right and you were to try it, the 15 amp breaker would just pop and that would be the end of it.

[Synther]

Absolutely not. Its possible if you want to burn your house down from an electrical fire. The draw would be far too much for 120V to handle.

The more realistic answer is yes, you can run an STH10 on 120v. The amp draw is way under 15A and no, you won't burn your house down. It'll just run at half speed or slower.

[Ohio_Man]

Absolutely not. Its possible if you want to burn your house down from an electrical fire. The draw would be far too much for 120V to handle.

You SURE about that?
An STH/L-10 is fused at 50 amp at 240 volts.
So the the current draw from the same load and half the voltage would be half the current.
So 25 amps. Mind you a 15 amp breaker which is typical for a run of the mill outlet would pop almost immediately.
But a 20 amp or 30 amp breaker, fed with the correct wire, would probably hold and run the motor up to not quite half speed.

That being said, if you would need to run a new circuit, why not install a CORRECT circuit with a proper 50 amp outlet and a manual disconnect (could use a 50 amp welding outlet)
and just be done with it.

But as far as burning down the house,,,, only if the wiring in the house was improper, the fuse / circuit breaker was improper would you chance a house fire over the attempt.
If everything was right and you were to try it, the 15 amp breaker would just pop and that would be the end of it.

"No Tim I don't think that's right" -Al Borlean, Home Improvement.

Volts X amps=watts.

The siren draws 50 amps at 240V. A motors wattage cannot be changed. If you run that motor at 120V, It will pull 100 amps.

And that's not including the startup surge, which if often 3x or more than the motor's pull, hence why old industrial setups had slow blow fuses (Think grain elevator conveyor motors, heavy water treatment plant motors, and overhead cranes).

Speaking of Home Improvement, if we gave the siren MORE POWER and ran it on 480V, the amperage would be a manageable 25 Amps. Of course federal signal would deny the warranty and the siren would increase in pitch to a sound like a dog whistle if it didn't over spin and destroy itself.

I also forgot to mention, more amps means more heat. So if you did somehow manage to start the siren on 120V it would run Very hot if it didn't just melt its own windings.

Now if you somehow wire 2 120V circuits in series that's 240 right there. I've seen this done temporarily.

Remember, when you're dealing with wiring you're playing with power.

Also why not just unplug your stove/dryer/farm welder and run it out of there? That's 240 from the mains and you don't have to do any wiring, just go to lowes , buy a plug, wire the plug to the siren with a good extension and away you go not dying.

[CanadianTbolt1003]

As uncommonsense and ohio_man said it would likely be not a good idea at all ohio_man is right the current/amps would be more than 60 amps on 120V likely 100 amps or more especially on the startup so the answer is no it can't run on 120V without frying the electrical system due to high amperage pull I'd suggest a model 2 for a siren to have as they are easy to power.

[Synther]

What's odd is it doesn't draw anywhere near 100 amps. Runs just fine, and the breaker would trip well before any fire would start (unless your electrical system was hooked up by idiots).

[Tboltguy]

The siren would be stored and ran at my rented storage unit so hooking it up to a dryer/stove would not be possible.

I did see a lot of variation, one guy said it’s super dangerous, one guy says I need to wire different circuits, one guy says it’d be fine, which is the definitive answer?

[Chem_Boffin_6589]

You can and it'll work, but it'll be painfully slow, plus it might trip a sensitive breaker if you're unlicky to have one. You'd be better off with a Model 7 because of your electrical situation.

[Ohio_Man]

If you do run a 240 off 120 can you tell us how many amps/volts it's pulling with a multimeter?

I think the voltage will drop significantly like in a brown out.

Also make sure the siren is single phase (2 wires) not 3 phase (4 wires)