Electricians, a questions about volts.

[Paul B]

I may have trouble with this because although I have been a construction electrician general foreman in Manhattan for almost 40 years I may retire next week (depending on our contract thursday)
I am trying to forget all I ever learned as an electrician.

If your load is 11.4 amps you will be fine with a 20 amp GFI or GFCI as you guys call them. A device doesen't actually consume volts. Volts are just the preasure that pushes the amps through the device. You get close to 120 volts out of the power company transformer on your street somewhere, depending on how far your house is from that transformer you will get a little less volts. It is really no problem though because your devices will draw more current if the voltage is less. It may also cost you slightly more but don't worry about that.
Your 20 amp GFCI will be fine on your 20 amp breaker with a load of 11.2 amps. A 20 amp breaker will let you use 20 amps. I know about the discussion that a breaker will only let you use about 90% of it's rated current continousely and that is sometimes true but not always. Many 20 amp breakers are happily passing 21 amps all the time with no problem except that they get hot and occasionally trip. They will usually hum if you try to push too much current through them.
Hello there Chevy.
Thank you all Veterans.
Paul

[jdieck]

Originally posted by alan214
I'm no electician so I'm not sure why it drops from 120 to 196.7 but I definitely can see it when I connect a DVM to an outlet when the central air kicks in.

The transformers in the street power distribution system have taps that change and adjust the voltage to the lines that deliver the power as the power draw gets increased so the voltage at the entrance in your house will remain fairly constant.
Having said that if you connect a high power consumption piece of equipement to an outlet there will be a large current flowing trough the wiring that go from the entry to the house (Main panel) and the outlet. The smaller the wire (the higher the gauge) the larger the voltage drop (and the more the wires will heat) between the entry to the house and the outlet generated. This voltage drop and heat is generated by the resistance of the improperly sized wires. A drop from the usual 115-120 to 97 volts is sizable and indicate an issue with your wiring. I would recommend having a licensed electrician properly size and replace the wiring for the intended load to prevent line overheating and a potential fire.

[jdieck]

As Paul mentions above, when an inductive load (Anything with a coil like a magnetic ballast or an electric motor) is connected to the line and the voltage drops the device will tend to draw the same wattage thus will draw higher current to compensate for the voltage drop.
During start up for an instant of milliseconds, inductive loads behave almost like a short circuit drawing in many instances twice as much current as they would under steady running conditions. For this reason is advisable not to exceed 70 to 80% of the rating of the wiring and breaker.
Finally regarding the lighting, if you have two bulbs of 400 watts note that those 400 watts are the nominal power load generated by the bulbs at the bulb end. In other words to those nominal 400 watts you need to add the additional power consummed by the ballasts itself (which turns into heat) thus at the outlet you will see the power consumption of the bulb (400 watts) plus the ballast consumption which for electronic ballast will be around 20 watts and for magnetic ballasts could be up to 40/50 watts including the loss generated by the reactive voltampere (The infamous power factor). So in summary for that lighting assuming your outlet provides 115 to 120 volts and the load will be around 900 watts the expected amperage will be between 8.3 and 7.9 Amps (roughly 8 Amps) at the outlet which will rought take 10 to 11 Amp out of your braker capacity leaving you with only about 7 Amps (800 watts) extra capacity in that outlet (or any other outlet connected to the same circuit.) if your breaker is 20 AMP or about 3 Amp (370 to 400 watts) if your breaker capacity is 15 Amp.
A final note of caution. Breakers are sized to protect certain wire size. Although tempting avoid replacing a 15 Amp breaker with a 20 Amp breaker unless the wires are also changed to a higher capacity. Doing otherwise you can invalidate the protection to the wires creating a hazardous condition due to potential fire and overheating.

[Kaiser Tang]

Thanks for all the info guys! Another question to ask. I'm planning on putting about 12 amps of equipment (a return pump, skimmer pump, chiller pump, and chiller) on one curcuit controlled by a wall switch. That way I can shut it all off for when I do water changes by just flipping the switch. Would there be any problems with fliping that switch and powering it all up at the same time?

[jdieck]

Originally posted by Kaiser Tang
Thanks for all the info guys! Another question to ask. I'm planning on putting about 12 amps of equipment (a return pump, skimmer pump, chiller pump, and chiller) on one curcuit controlled by a wall switch. That way I can shut it all off for when I do water changes by just flipping the switch. Would there be any problems with fliping that switch and powering it all up at the same time?

Note that pumps and chillers are all inductive loads and specially the chiller will draw a large current on start up. Although you can find toggle switches rated for 20 A / 120 volts for this kind of load the switch life will be significantly shortened.
I would suggest using three independent switches not only because of the load but because of practical purposes. With three switches it will be easier to take each piece of equipement out of service for replacement and maintenance. I would install an outlet after each switch to physically unplug the device for safety during servicing and for easy of removal.

[Frick-n-Frags]

in a word, no problem unless your GFI doesn't like that particular load on startup and trips (sees the inductive delay imbalance and thinks there is a short to ground) the bigger the winding, the bigger the inductive time-delay and the better chance of a trip.

you could get one of those american DJ 8 outlet'individually switched power centers to plug into that main circuit and selectively turn things off and on, and even if turning them all off and on, they can be done one at a time.

[Crusty Old Shellback]

Or you can go to home depot or any other such store and buy four switched outlets to use one for each peice of equipment. Thatw ay you can plug each peice of equipment into it's own plug and have a switch for it. You can gang them all together and plug the source into your outlet. Then by doing such, you can turn them off all at once if need be with the main switch and turn them on one at a time with the individual switches.

I have my system set up similar to this in that I have three 20 amp circuits run to my tank. Each circuit has a regular 2 outlet wall socket near the tank. From there I use a normal plug and run the wire to the area of the stand I need and built a small electrical distribution center with the switched outlets. I can then plug in pumps, heaters, lights, etc. and am able to turn off each peice of equipment individually. If need be, I can turn off the breaker at the source and kill the whole circuit.

One other note to add on what Paul and jdieck have stated that I have found from working with shipboard electrical systems. A brand new breaker will usually trip right around the rated current draw it is designe dfor. As time goes on, each time the breaker trips, it actually weakens the trip device and will lower the current draw point at which the breaker trips. So if your running at or near the rated capacity of the breaker, and you continually trip the breaker on start up, eventually you will weaken the trip mechanasim to the point where it will trip at a value less than waht it's rated for and will then also be below the load you have on the circuit. That is anothe reason why they say not to run the circuit at it's max rated capacity all of the time.

[Paul B]

Yeah, what Chevy said.
Also there would be no problem switching 12 amps with a single switch. Office buildings generally run the circuits at almost capacity for lighting where there are numerous ballasts on a circuit. Breakers are designed to allow much more amps to pass for an instant than they are rated for. Sometimes when we can't find a circuit breaker we short the wire to ground to trip the breaker. Very often we just can't trip the breaker for many seconds when there is probably 50 amps passing through a 20 amp breaker. I know, I know, we are not supposed to do that but when you do this all the time sometimes you just have to.
The old fashoned glass plug fuses were much safer than breakers but you diden't have that extra capacity to start high draw appliances and for 220 loads usually only one fuse would blow sometimes causing an unsafe condition. We also could not use them with a GFI.
Being an electrician my wiring is a mess. I diden't build one of those nice switch panels that people post. I just have a bunch of wires plugged in to a bunch of receptacles. But then again, I never tripped a breaker on the fish tank.

[Crusty Old Shellback]

Come on Paul,
You, the master electrician with a almost 40 year old tank, and you've got a wiring nightmare instead of one of those pristene wiring switch setups?

At least you never tripped a breaker.

[Kaiser Tang]

From what everybody has told me, I have been able to roughly calculate my amperage and I believe that I'm on the right track. Right now, I have two 20 amp curcuits going to my tank. (Both equiped with a 20 amp breaker and a 20 amp GFCI.) I have 10 outlets per curcuit. I have calculated max load for one curcuit is about 12 amps and the other curcuit is about 15 amps. (assumming that (2) 300w heaters are running at the same time.) I probably will invest in a switch board so that I can turn my pumps and chiller off individually. If needed, I can bring in another curcuit. But it sounds like that it won't be neccessary unless I add something. I can't image adding anything else that would have a large power draw.

[Crusty Old Shellback]

What about changing out the 10 outlets to switched outlets? That way you can turn off each piece of equipment individually. Only problem would be you would have 5 outlets instead of 10 but you could always add to them.

[Paul B]

At least you never tripped a breaker.

I probably have them taped so they don't trip

I run my electrical panel like my tank. I know how to make it beautiful but I save that for the paying customers.
Neat electric like a neat tank does not mean better.
Well sometimes it does

[Kaiser Tang]

Originally posted by blown63chevy
What about changing out the 10 outlets to switched outlets? That way you can turn off each piece of equipment individually. Only problem would be you would have 5 outlets instead of 10 but you could always add to them.

I'm mot going to say that I couldn't have done that, but it wouldn't have been practical. Because of where my tank is located, I don't have a room or something on the otherside of the wall where I could put a switch board.

Here's a pic of where my tank is going and what I have done so far. All of the outlets on the left are on one curcuit and and all of the outlets on the right are on another. At the bottom, there is a GFCI that controls the outlets above. The outlets way up top are for powerheads, back-up air pumps (battery operated but have to be pluged in to detect power failure) moonlights, etc. The outlets below are for pumps, chiller, lights, heaters, etc. The are enclosed in waterproof boxes becuase they will be at sump level and expose to possible splashing, salt creep, etc. I was considering at first putting a toggle switch on the wall to the left to control the outlets on the left. The wife would only let me put in one switch. She wouldn't go for multiple. I really don't have room underneath the tank due to my sump and other equipment. So, right now the small "DJ" type switch board looks like a good option.

[Paul B]

Here is a picture of the safe way for a reefer to wire a panel'

[vapor1]

I think I have seen that electrician before...ROFL

[Crusty Old Shellback]

Paul,
Is that you in your younger days?