What does this Electric Box contain? Does it emit harmful radiation?

Thread Starter

Trifux

Joined May 15, 2022
10
What does this box contain?


Hello. I was wondering what would be inside this pharmacy cross sign box (the sign emits light during the day) and wether or not it could be harmful to be nearby for a long time since this is installed just below my office window (1 meter away or so)

Thank you very much!
 

Ian0

Joined Aug 7, 2020
5,097
It's a power supply for the sign. By the looks of it the sign is made of a series of high voltage argon discharge tubes. It's harmless (unless you stick your fingers in it)
 

Ramussons

Joined May 3, 2013
1,262
Any gas discharge will also emit Xray's, though the intensity may not have any immediate effect.
It is possible that there may be unwanted effects in this short distance and long exposures.
 

Thread Starter

Trifux

Joined May 15, 2022
10
Any gas discharge will also emit Xray's, though the intensity may not have any immediate effect.
It is possible that there may be unwanted effects in this short distance and long exposures.

Any gas discharge will also emit Xray's, though the intensity may not have any immediate effect.
It is possible that there may be unwanted effects in this short distance and long exposures.
Can you please elaborate?
 

Ian0

Joined Aug 7, 2020
5,097
I think that a green sign will be an argon lamp with a phosphor coating which emits green. There will be some UV emission, but it is attenuated by both the glass of the tube and the glass cover.
If you stand in front of your microwave oven watching it cook, you'll probably be putting yourself in far more danger than a "neon" sign outside your office!
 

Thread Starter

Trifux

Joined May 15, 2022
10
Can you please elaborate?
I think that a green sign will be an argon lamp with a phosphor coating which emits green. There will be some UV emission, but it is attenuated by both the glass of the tube and the glass cover.
If you stand in front of your microwave oven watching it cook, you'll probably be putting yourself in far more danger than a "neon" sign outside your office!
Thank you! But how can a discharge tube emit x ray? It kinda makes me think that it could be harmful to be somewhat close to x ray emission for longer periods of time every day.
 

nsaspook

Joined Aug 27, 2009
9,726
Thank you! But how can a discharge tube emit x ray? It kinda makes me think that it could be harmful to be somewhat close to x ray emission for longer periods of time every day.
Detectable X-ray emission unlikely at the acceleration energy of ions/electrons in a typical lighting discharge tube. The mean time between collisions (that cause the light) is too small in a gas filled tube not specifically designed for x-ray generation.

Don't do this at home. :eek:
Connecting a high voltage DC source to generate arcs inside a incandescent bulb from the base to a ground plate on the top will produce x-rays because inside the bulb is a pretty good vacuum (long mean free path) that allows the much of the acceleration energy on the particles from source to target.
 

Thread Starter

Trifux

Joined May 15, 2022
10
Detectable X-ray emission unlikely at the acceleration energy of ions/electrons in a typical lighting discharge tube. The mean time between collisions (that cause the light) is too small in a gas filled tube not specifically designed for x-ray generation.

Don't do this at home. :eek:
Connecting a high voltage DC source to generate arcs inside a incandescent bulb from the base to a ground plate on the top will produce x-rays because inside the bulb is a pretty good vacuum (long mean free path) that allows the much of the acceleration energy on the particles from source to target.
Thanks for the explanation! Will you consider then any danger of being close to the neon sign for long periods of time every day?
 

Tonyr1084

Joined Sep 24, 2015
6,884
X-rays were called EX RAY because the radiation they emitted was not known or understood. The sun is a form of radiation. So is an incandescent lamp. Radioactive materials emit x-rays because their particles are deteriorating at a known pace. THOSE emissions are hazardous because they cause ionization in living cells.

Microwave ovens don't emit x-rays they emit micro waves. Yes, very small electromagnetic waves of energy. Those interact with water molecules causing them to vibrate at very high rates. That vibration generates friction, which generates heat. That's how a microwave oven works. Fluorescent lamps create ultraviolet light waves which are then turned into visible light by the phosphorous coating inside the glass tube. I'm sure some UV light leaks past, but not much. And when you're at a certain distance and you double that distance you reduce your exposure by four times. It's called the inverse square law. If you shorten your distance by half - you increase your exposure four times.

With true radiation - what we think of when we think of Nuclear Reactors and X-Ray photography (like at the doctor or dentist office) those can penetrate soft walls like sheet rock. The harder and denser the materials the more shielding you get. But with UV radiation - a paper napkin can block much of the UV. A sheet of paper can block a major percentage of UV. A wall - forget about worrying. It's not going to get to you. And as I mentioned before, the further away you are the much less radiation you'll get.

If your office has fluorescent lights - you have more to be concerned from them than you do from a sign that is outside the establishment. And you literally have nothing to worry about with fluorescent lights in your ceiling or on a desk lamp. They're 100% safe.

Now, I've never heard of a green cross for a pharmacy. I've seen Rx, for which I don't know what that means, and I've seen the snake on a pole (comes from the bible). But never a green plus sign. I'd be more inclined to think that plus sign is a school for the mathematically challenged.
 

AnalogKid

Joined Aug 1, 2013
10,054
it could be harmful to be somewhat close
For this type of sign, "somewhat" means inches.

Separate from that, note that this is a sign. It's job is to emit light in specific directions. In your photo you can barely tell that it is lit because you are not in front of it. That is significant. Also, the brightness of the world around it is much higher, giving you a context for just how much energy this thing is emitting - way less than daylight.

You are too far away and too far off-axis for anything radiated by the sign to be significant.

ak
 

Ya’akov

Joined Jan 27, 2019
5,659
Now, I've never heard of a green cross for a pharmacy. I've seen Rx, for which I don't know what that means, and I've seen the snake on a pole (comes from the bible). But never a green plus sign. I'd be more inclined to think that plus sign is a school for the mathematically challenged.
The green cross is a long standing symbol for first aid. I don't see it used as much anymore, and some times a red cross is erroneously used instead, but that's what the green cross meant for a very long time.
 

AnalogKid

Joined Aug 1, 2013
10,054
OK, all of the talk about argon misled me; I see now that your question was about the box. That is a high voltage power supply. Old school, it is just a big transformer. Nowadays, it might be a switching power supply. In either case, it is in a steel box so it is emitting *very* little radiation of any kind, and that is mostly electrical noise. Plus. it must meet FCC rules restricting such emissions to levels that are both safe for humans and do not interfere with other electronic equipment (radios, computers, etc.).

Even without the steel box, it does not radiate enough of anything to be harmful to people.

ak
 

Reloadron

Joined Jan 15, 2015
6,584
What does this box contain?


Hello. I was wondering what would be inside this pharmacy cross sign box (the sign emits light during the day) and wether or not it could be harmful to be nearby for a long time since this is installed just below my office window (1 meter away or so)

Thank you very much!
In the box is the power source for the sign. Older ones used a transformer as pictured below.
Trans2.jpg

Newer units use a electronic power supply rather than a old transformer type supply. Neither will harm you or emit anything which will harm you. You have seen neon signs as they are commonly called and pretty sure if they released anything harmful their use would be prohibited.

Ron
 

MisterBill2

Joined Jan 23, 2018
11,877
Within that steel box are circuits that provide high voltages that are dangerous. THEREFORE it is important for your safety to not open that box.
But as long as you leave that box closed completely and do not open it there is no shock hazard from the contents.
 

Ian0

Joined Aug 7, 2020
5,097
The green cross is a long standing symbol for first aid. I don't see it used as much anymore, and some times a red cross is erroneously used instead, but that's what the green cross meant for a very long time.
The green cross is gaining popularity in Britain. It is very popular in France and Germany, where all the segments are controlled separately from a light chaser running at a frenetic speed - just the sort of thing to give photosensitive epileptics a seizure.
I don't know where the TS is, probably not Britain because the vehicle in the pictures is left-hand drive, but the badly painted single-yellow no-parking line looks British!
 

Ian0

Joined Aug 7, 2020
5,097
Now, I've never heard of a green cross for a pharmacy. I've seen Rx, for which I don't know what that means, and I've seen the snake on a pole (comes from the bible). But never a green plus sign. I'd be more inclined to think that plus sign is a school for the mathematically challenged.
Snake-on-a-pole is ancient Greek - it is the Rod of Asclepius and it should have just one snake!
https://en.wikipedia.org/wiki/Rod_of_Asclepius
If it has two snakes, then it's the staff of Hermes the messenger and it's called a Caduceus
https://en.wikipedia.org/wiki/Caduceus
https://en.wikipedia.org/wiki/Caduceus_as_a_symbol_of_medicine
 

MisterBill2

Joined Jan 23, 2018
11,877
Upon an even closer examination of the photo attached to post #1, that sign might be an array of green LEDs sealed in plastic tubes. If that is the case then the adjacent steel box would contain a lower voltage regulated power supply.
Thus as long as hands do not grab inside the box there would be no hazard, and certainly no radiation.
 
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