Adding a Sub and a Generator

[scottgjerdingen]

I am a homeowner seeking advise and hope you could help me out.

I recently put an ~ 500 gallon aquarium in my home. It is a saltwater tank and has enough equipment running off of it that I want to bring in 2 20 amp circuits just for it. My idea was to have a 60 amp sub brought over to the area where all of this is and have 2 20 amp lines run off of this. Also, because the saltwater fish and corals are delicate the cannot stand power outages I have a backup Generac generator (7500watt/13000watt surge) and I am looking to have this wired into the house as well via some sort of 60 amp transfer switch/circuit to the main.

It was alternatively suggested to me that this getting the 2 new circuits and wiring the generator such that electricity could be supplied to them in the event of an outage could be accomplished by installing a 60 amp "generator panel" that would have the 2 new 20 am circuits on it and would be connected to the generator (and there would be one open 20 amp slot to connect the furnace and maybe a refrigerator).

Personally I feel the second option 2 unrelated needs together via a single solution and doesn't address either need as best as possible. First, by running the circuits for the furnace and fridge into the 3rd 20 amp slot on the sub I have taken away the ability to open a 3rd 20 amp circuit for future aquarium demand. Second, given an outage situation the first option seems to provide me with the flexibility of selectively powering a variety of things (tv, lights, phone, ac?, furnace, etc.) as long as I was careful to keep below say a 60 amp draw on the generator. Given the second option, the only thing I could power via generator would be stuff wired into the generator panel (aquarium stuff, furnace and the fridge) and since in this situation my aquarium usage would be minimized (e.g. would not be running my 3000 amps of lighting) I would have excess generator capacity that I could not tap into w/o breaking out extension cords which then kinda defeats the purpose of wiring this into the house in the first place? I suppose there is merit to both options and one possible compromise is using one of those 8-10 circuit transfer switches that can be wired to specific circuits that I can turn on and off as needed...but I do think I am aware enough realize the when the generator is on demand should be kept to a reasonable minimum (e.g. no hair dryer, laundry, dishwasher, minimal things all on at the same time, etc.) and 60 amps is a fair amount of electricity for a smaller home).

So, can you possibly explain to me why the first option is bad and/or the second option is better and even better yet, can you specifically suggest the best method of accomplishing what I am driving at in option 1 (also, I am working on a budget and will need to get a professional that can do this for as much under $2,000 as possibe - I need to also fund an inverter to hold the aquarium over until I can get the generator started )

Thank-you in advance for your help and cooperation!

- scott -

 

[rich000]

Re: Adding a Sub and a Generator

There are numberous issues here.

First, what is the demand of your tanks (filters, heaters, and lights)?

To say that they need (2) 20A circuits is alot. A 20A circuit can be loaded to 1800W safely.

The first option is obviously the best, because you can chose the loads you wish to power.

The cost issue depends on where you are and what materials you are providing. $2000 sounds a little tight.

Good luck.

 

[luke warmwater]

Re: Adding a Sub and a Generator

There are many brands and types of transfer switch systems. Generac has a transfer switch that is pre-wired. You just mount it beside and wire it into you electric panel.
A 500gal. tank in a home is HUGE . That is going to require more than one filter, a couple heaters, chiller (or 2), ozonizer, power heads, etc., not to mention lighting. Two 20amp circuts seems modest.
$2000.00 seems very tight indeed. Is the inverter included in your budget? And if you use an inverter, you'll need a battery. And then you'll need a second transfer switch to operate between generator and inverter power. And you'll need a battery charger for the 12v. battery.
I don't think it could be done by my company for under $2000.00

 

[scottgjerdingen]

Re: Adding a Sub and a Generator

Thanks for the replies and I will try to address the questions you pose.

I already have the tank up and running now and through enforcement have 2 dedicated circuits running this.

I think I have pretty much done my homework on the demand, at a high level this is what I will be running;

lighting - 1600 watts (13.5 amps)
pumps - 1500 watts (12.5 amps)
heaters - 500 watts (4 amps)

The tank is a reef tank so I am not running any mechanical filtration (although if need be I may add ozone at a later date to get the water crystal clear), tank is in a Minnesota (outside Minneapolis)lower level so there is no need for a chiller. So I am pushing the 2 new circuits to the max, but in reality I will be spreading some of this out over an existing circuit as well (not only for reasons of consumption need but for redundancy...if a GFI trips and kills all of my pumps the stuff in the tank will be dead within hrs)....so I think the 2 20 amp circuits will meet my need, or am I wrong?

As far as supplying materials goes, I guess I had heard that some electricians mark up material cost 300% so maybe I can defer cost by picking up the materials myself, but then I would need advise on what exactly to purchase so that the electrician would be happy w/ my selection...any recommendations?

As for the budget, I had planned on $800 to $1000 to wire in the sub and the 2 20 amp circuits each having 1 4 way outlet I could tap into. I had planned about another $1000 to wire the generator into the main panel (and saw this as a separate project that I could do now or later). Likewise I saw the inverter as an overgrown UPS that I could take care of for ~ $400 via a 500 watt inverter and a couple deep cycle marine batteries (only need to power the main pump with this for a few hrs).

So, kinda back to my original question, shy should I wire the generator into the new sub and limit what it can power vs. wiring it into the main and use what I need?

Thank-you in advance for your feedback!

- scott -

 

[rich000]

Re: Adding a Sub and a Generator

You are right luke.

I looked up some power requirements and the heater alone suggestion is 5 watts per gallon.

 

[luke warmwater]

Re: Adding a Sub and a Generator

Scott, the 2 circuts will squeeze by for now but I would add a third circut if possible. I would imagine all of the stuff to be on for more than 3 hours at a time.
I would try to get a few estimates.
People always think that they are getting 'ripped off' when the contractor supplies the materials. It's not always the case. The contractor should know exactly what is needed to do the job. And as you stated, you would need a list. We charge for this information. If you are going to supply materials, make them specific materials, known to whoever is bidding the job. That way they can get all of the little things that get forgotten : ie. screws, wirenuts, staples, connectors, etc. 300% mark up sounds high to me.
To answer your original question, the only thing that I could think of was to control the load of the generator.
But to incorporate an inverter, you would still need a second transfer switch, otherwise you would have to be plugging and unplugging cords, not the safest method.
I understand your concerns- saltwater fish can be very expensive.

 

[luke warmwater]

Re: Adding a Sub and a Generator

Check out this site: That Fish Place
I've shopped here for 12+ years. They are located in Lancaster, PA

 

[scottgjerdingen]

Re: Adding a Sub and a Generator

I wasn't terribly concerned about being "ripped off" on parts, I know how this works in other industries and this is something I need to evaluate in reviewing estimates.
What I am concerned with is not knowing what is best and if what I want is sound? I want a dedicated 60 amp sub for my tank and the generator wired into the main. When I asked 2 electricians to estimate this they both wanted to add a 60 amp "generator panel" w/ 2 20's going to my tank and the other 20 powering my furnace and upstairs fridge (in neither case was I home when they surveyed the job, but I did provide a written description of what I wanted...maybe I was not clear enough?).

I feel my electricians suggestions are limiting in terms of accommodating future demand needs in the tank area as well as powering stuff when the generator is in use. But in fairness to those submitting the estimates, maybe what I want does not meet code? Is what I want to do wrong, is what is being suggested to me better?

As for the inverter hookup, I have not researched this much but it was my understanding that it could be hooked up pretty much like a UPS and would power on automatically when loss of power was detected.


Thanks Agqin!

- scott -

 

[rich000]

Re: Adding a Sub and a Generator

Thinking about this again, I would not wire it the FIRST way into the main box. There is the potential to overload the generator unless the generator is sized to protect the whole house.

The typical installation is for the loads that you want to back up to be fed from a generator transfer panel. Normal power comes to this box from your house panel and emergency power comes from the generator. This way, the total load does not exceed the generator's capacity.

Whether or not YOU know how to operate the system if the generator is hooked up to the main panel is not the point. Someone else behind you may not know how to operate it. Unless you install safeguards to prevent the overloading of the generator, I would not wire it to your main panel.

For future considerations, by a transfer panel that can accomadate future loads. Then if you get a larger generator, loads can be added to the panel.

Here are some code references:

700-5(a) Capacity and rating. An emergency system shall have aqequate capacity and rating for all loads to be operated simultaneously. The emergency system equipment shall be suitable for the maximum availabel fault current at its terminals.

700-6(a) ...Transfer equipment shall be designed and installed to prevent the inadvertant interconnection of normal and emergency sources of supply in any operation of the transfer equipment.

In regards to the UPS: If the tank epuipment is plugged into the UPS and the UPS is plugged into the wall, then the power would come from either the normal or emergency source, nothing special there. However, most UPS systems have a difficult time recognizing that power is available once the generator comes online. It is called UPS/Generator compatibility. You may have to force the UPS to come off battery. This is typically a problem in larger UPS units. Check with the UPS manufacturer to see if it will work with your generator. The tolerance of voltage of the generator has to fit into the UPS voltage tolerance, otherwise the UPS will keep flopping and going to battery.

 

[gregory]

Re: Adding a Sub and a Generator

I am curious as to why the fish tank can't do with out lighting for a couple of days. is it really necessary to have constant lighting for these fish? I would not recomend using the marine deep cycle batteries for your inverter storage batteries. The have many very thin plates for storage that will not last more than a year or two. You should invest in a golf cart type batteries for your storage. they have large thick plates and should last between 10-20 years. you will also have to buy a trickle charger to keep your batteries topped off. I think that your $400 allowance is to meager. your allowance should be at least $1000.00

 

[hurk27]

Re: Adding a Sub and a Generator

700-5 is only for a required emg. back up generator not a home gen set for general back up power.
most gen-sets that are on the market are supplyed with transfer panels that far exceed the power capabilty of the generator. and include instructions with it to advise the home owner to watch how much they can turn on at one time when on the generator. and what he is asking is not to unresonable. but it will requir that the transfer switch to be rated for the service IE. it he has a 100 amp service the transfer switch has to be rated 100 amps. this will also give him the ability to up size the generator at a later date if it is so needed. the breakers on the generator will protect the generator in the event that he turns on to much equipment.