Ah schucks, don't just go away on us like that. I was looking forward to you explaining this:
You see many 200 amp services where the two hots are sized for 200 amps and the neutral is sized for 400 amps? Where do you buy that cable? There is never more than 200 amps in any conductor. Nor does there have to be to support 400 amps of 120V load on a 240V, 200A service.
Arguing any point of fact with trader is a total waste of time and bandwidth, and means I have to see his (reposted) drivel.
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I own a tanning salon and want to add couple more beds.. however I only hav e a 200 amp service. We currently have 5 tanning beds, all are running on 2
40v, when we checked with all the beds on the amp draw at the main was 196 amps. When I then turned our towels dryer on the amp draw was 216 amps, but it did not trip the breaker. In addition we have all the other lights and central air and curling irons turning on and off etc etc. So how far past the 200 amps can I go before it will trip? The tanning beds only run for 20 mins.. so even if all the beds are on at the same time they never are all on for longer the 20 mins at a time so being past the 200 amps is only cons istant for 20 mins. So could someone please give me an idea how far past t he 200 amps I can go so I know if I can add another bed or 2? Thanks!
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I own a tanning salon and want to add couple more beds.. however I only have a 200 amp service. We currently have 5 tanning beds, all are running on
240v, when we checked with all the beds on the amp draw at the main was 196 amps. When I then turned our towels dryer on the amp draw was 216 amps, but it did not trip the breaker. In addition we have all the other lights and central air and curling irons turning on and off etc etc. So how far past the 200 amps can I go before it will trip? The tanning beds only run for 20 mins.. so even if all the beds are on at the same time they never are all on for longer the 20 mins at a time so being past the 200 amps is only consistant for 20 mins. So could someone please give me an idea how far past the 200 amps I can go so I know if I can add another bed or 2? Thanks!What you asking it is not simple answer. The circuit Breakers are not instantaneous they act as time delay it takes few minutes to warm-up before it will drop out. However I would not advise you to run even 196 amps. for longer time connection and wire could fined small amount of resistance that could cause the fire, Good luck
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As I pointed out.. the tanning beds operate for no longer then 20 mins. So that would be the maximum time spent above the 200 amp line. But I still wo uld like a better answer as to how far past I can go before I start trippin g the main. In earlier posts I read that only after a sustained amp draw of 3 hours would it trip. If this is true then I shouldnt be anywhere clos e to having a problem if I am only doing 20 mins then a break then 20 mins etc. So could I go to 250 amps? or more? I understand what I am asking is pushing the rules, but would like a reasonable idea of how far past I can g o. I want to purchase one more bed and if that puts me at 210-220 amps for
20 mins at a time, just want to know that I can do that without tripping my main etc.Thoughts?
doing 20 mins then a break then 20 mins etc. So could I go to 250 amps? or more? I understand what I am asking is pushing the rules, but would like a reasonable idea of how far past I can go. I want to purchase one more bed and if that puts me at 210-220 amps for 20 mins at a time, just want to know that I can do that without tripping my main etc.
Forget about trying to push the limiits of the breaker. If you already have a load of close to 200 amps, either forget the other bed or upgrade the service.
You are not only pushing the limits of the breaker and may weaken it to where it will trip at a lower current at a later time, you are chancing over heating the wires feeding the breaker.
Looking at some typical tripping curves it could take from 1000 to
10,000 seconds if overloadded to about 120%. The more the overload, the faster the tripping.It is also the ammount of heat build up. If the box is cold as in the winter time, the times will be longer and if hot as in the middle of summer, the times will be shorter.
This is true.
15 years ago, a so-called "scientist" with a radio show and a doctorate degree, was advocating for the local utility to manage power shortages by installing a device on power poles that connected all the 120V loads, in both legs, together, which would turn off all the 240V loads (A/C, pool pumps, dryers, stoves, ovens, etc.). One 120V leg would power all the 120V outlets.As one person pointed out, that would cause a lot of old houses to burn down since the neutral in older houses was not designed to carry these loads, since builders saved money by using smaller neutral conductors. With a balanced load in each leg, there is relatively little current flowing in the neutral. Newer houses have a neutral that can handle the "maximum unbalanced load."
"Scientists tinkering with electric switches at Lawrence Livermore National Laboratory may have found a way to prevent blackouts across California. Researchers at the lab in the past week have successfully tested a simple electric switching device that could be placed on thousands of power poles around the state, shutting off partial power to homes and businesses during Stage 3 alerts in hot summer months, while keeping some lights on."
Fortunately, PG&E was not foolish enough to take these "scientists" seriously.
Maybe you could get a few more watts out of your panel if you installed some PC case fans to cool the breakers?
/sarcasm
So that would be the maximum time spent above the 200 amp line. But I stil l would like a better answer as to how far past I can go before I start tri pping the main. In earlier posts I read that only after a sustained amp d raw of 3 hours would it trip. If this is true then I shouldnt be anywhere close to having a problem if I am only
r more? I understand what I am asking is pushing the rules, but would like a reasonable idea of how far past I can go. I want to purchase one more be d and if that puts me at 210-220 amps for 20 mins at a time, just want to k now that I can do that without tripping my main etc.
+1 to all that.The OP is right at 200A with the existing 5 beds. The dryer makes it 216A. Five beds, 200A, the beds are 40A each, so how can they add a couple of new beds? Even one puts it at 240A/256A. And in line with what you're saying about warming up, once tripped, if it's reset, it's going to trip faster the next time. Doesn't sound good with a business with 6 customers.
Side note, I'm having a hard time figuring out where all this power is going. That's 10KW for one bed. I've never been in one, but I thought they put out UV, not a lot of heat. 10KW sounds like enough power to start cooking you, similar power to a home oven.
They are cooking you. If the beds are commercial units they can use from 10 to about 20 KW. The time is about 5 to 15 minutes depending on how much you want to tan.
I have not been in one either, just going by the specifications of them.
It does not mater if it is UV light or just heating units all of the power will be converted to heat. Not sure how much the person will carry out with them.
If the beds are that big he probably also needs to up the air conditioner by about another ton.
Wire properly sized presents no risk, so IDK what the alleged problem with wire heating is when the draw is within the 200A rating, there is considerable margin. And resistance is resistance, so a bad connection with resistance X is going to create the same heat with 196A flowing through it on a 400A service as it will on a 200A.
If you apply 240-Volt to the load and have 200 Amps current, you've got 48 KVA. If you apply 120-volt and have a 200 amps, you've got 24 KVA. If you connect 200 Amps load to each of 120-volt leg, you've got 48 KVA total.
In other words, if you balance the load and use only 120 volt loads, you can run a maximum of 400 amps. If you run only 240 volt loads, you can only run 200 amps
Technically, yes, but 80% max is recommended
And no 400A anywhere.
That is just a guideline for some individual loads and a rule for others. When you do the load calc for the whole service, you can install based on 100% of the result if you are being cheap. The NEC is not a design manual, it is just a minimum standard.
And oftentimes the pole transformer is not capable of 48KVA. Most of them have their KVA rating painted right on the exterior of them. (You may need binoculars to read it from the ground).
And dont forget that they often supply power to other homes and/or buildings as well.
In reality there is never more than 200 amps of current flowing in a 200A service. If it's a balanced load, the same 200A is flowing through half the 120V loads, then on through the other half of the
120V loads. There is never more than 200A flowing in the service conductors. You can support 400A worth of 120V loads, but it's just 200A being counted twice.
Transformers supplying multiple homes MAY not be capable of supplying the full load of all the houses at once. Any single residence transformer WILL be sized to handle the full load - at least in Ontario.
I was unable to install a 200 amp sewrvice in my home because the transformer feed/undeground cable was lot large enough. I was limitted to 125 amps.
That is certainly not true in the US. They will feed 3 houses from a
50 KVA unit and assume it will handle spikes above the 50 KVA. My house os one of 3 on a 37 KVA unit. The guys told me, they will replace it with a 50 when we burn it up. These houses have 200a panels but they are fed with 2ga 1350 alloy aluminum overhead service conductors. Voltage drop has not been a problem here for me. I still get 124 or soHave something to add? Share your thoughts — no account required.
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