Placement of Lead-Acid Batteries & NEC Code

[RogerAS]

Hi All,

There is a thread over in the Newbies section regarding the placement of Lead-Acid batteries in the basement of a residence. One may read that thread here.

LINK

I have contended form the beginning that this was a bad practice and pointed out my various concerns. Instead of what I feel were reasoned responses there has been some conjecture and opinion which I feel are not only misguided but dangerous. I pointed out that the dangers of Lead-Acid batteries are well known and that such a practice was unsafe, could void ones homeowners insurance and maybe was illegal. After extensive internet research it seems I was right on all counts.

It seems highly irresponsible to offer adivce that places anyone in a situation that indangers life and limb, is a violation of the law and has no basis of support by logic or reason.

If you fear the effects of cold temperatures have on the output of your batteries I suggest you find a safe way to keep them warm, and NOT place them anywhere within a residence.

I am not attempting to demean those with other views nor am I here to toot my own horn. The ENTIRE motivation for this posting is to keep our interest in RE safe and responsible. If you the reader has a problem with those aspects of this endeavor no reference, no matter how authorative, will be of value to you. If you feel that you are more knowledgeable in this matter and none of this applies to you I have no more to offer.

Please read this citation and judge for yourself. There are other references out there, but this one settles the matter in a manner without dispute.

Photovoltaic Power Systems And the 2005 National Electrical Code:

Suggested Practices

BATTERIES

In general, NEC Articles 480 and 690 VIII should be followed for installations having storage batteries. Battery storage in PV systems poses several safety hazards:

Hoping the issue is settled,

[TomW]

Roger;

Well, I am not going to argue this but I really feel that some definition are in order.

Such as, but not limited to the "official" definition of "living area", "enclosure" and "below"

I suspect most systems have the battery as the lowest point [due to weight] so that confuses me some.

A link or 2 might be a good addition, also.

In my case, mine are in a building that is not covered by insurance other than the "outside electrical" rider due to distance from the house proper [>100 feet]. I do occupy the space occasionally for short periods of time but would not consider it to be "living area".

More questions than anything.

I might add that I have several friends who are electricians and every one says the code is interpreted by the local inspectors and can have pretty broad interpretation on the common and normal things so this rather obscure battery centric code passage probably is even more open to interpretation.

Not to argue but to seek clarification.

Note to others attempting to post to this: You need to remove the "&" in the subject or you get the long subject error.

Cheers.

TomW

[RogerAS]

Tom,

No problem with another link. Here ya go:

LINK

Quote from that site below:

 

Seems pretty clear to me, by residential architectual standards.

I know it's much easier to keep an eye on those batteries when they're in a living area but it doesn't seem to be an accepted practice by professionals in the field. Also, as I've stated before, it doesn't seem reasonable or logical to place risk, how ever slight this risk might be, to ones family and financial investment for the sake of ease.

I'm REALLY not trying to be judgemental at all about this issue, but feel very strongly that the importance of safety cannot be overlooked or dismissed out of hand.

You may well be correct in questioning the application and interpretation of the code in local jurisdictions. I contend that RE is so "outside the norm" that these jurisdictions may have never read that section of the NEC. It is also possible the these local enforcement officers have never seen an RE system at all. I do not feel this invalidates or nullifies the NEC code. Besides, I've personally seen building inspectors paid to NOT see some things, such as dirt added to a concrete foundation to bring it up to grade level. This in no way makes the practice "right".

I have uploaded the PDF of this section of the NEC code to my files. Here is the link to that.

LINK

Deffinitions of these terms may be a case by case issue. Some people may place their batteries on racks above the ground, or floor, level in which any electrical equipment should not be situated "below" the battery rack. I would conclude that any "living area" would be considered connected to, or a continuous portion of, an area of a structure in which people occupy on a regular basis.

I would not consider the area where you currently have your batteries to fall under the "living area" definition. If these batteries were in your bedroom closet, or under the same roof where you spend 95% of your time indoors, I would consider them to be in the "living area".

I am not trying to dictate to others what they HAVE to do, but rather point out that it just doesn't make sense to place batteries where they could ruin ones life in the event of failure. Imagine how one would feel if their house were destroyed by a freak accident that could have been easily avoided. Imagine how one would feel knowing they could have taken very simple measures to assure that tragedy, or much much worse (losing a loved one for example), never happened.

I hope stephent will comment here, as a master electrician I value his input a great deal.

As I stated before, my intent is NOT to piss folks off, but rather provide information that will help RE folks make sound choices with safety in mind.

(Sorry about the "&" in the title)

[SparWeb]

Roger,

Thanks for the PDF.  I've been reading the basic NEC code for a while and trying to relate the topics to what I'm doing.  This will be much more straightforward.  The examples in it are also of great value.

[mtbandy]

Hmm... I have a 344Ah bank 3 feet from my bed, probably I should re-think things a bit! I couldn't open the PDF (need to upgrade my version of adobe reader) but would the same risks still apply to sealed batteries? I cannot really see what could go wrong except a phenominal current surge should the thing ever somehow short out. I'm connected to a charge controller that cuts off at 14.2 volts, so the cells never gas (I did once accidentally knock the switch on top of the charge controller, and the cells instantly began to gas as the voltage rose up past 15!)

Of course if they were flooded cells I wouldn't even consider putting them in the house due to hydrogen build up within the case leading to possible explosions.

[stephent]

I agree with RogerAS on the NEC requirements.

The book is "usually" rather specific.

It's tough ($$) to follow the NEC battery storage/use requirements and do it right.

But that cost is opposed to doing it wrong at what cost?

[RogerAS]

MT,

It isn't up to me to tell you, or anone else, one way or another what to do. I want to stress the point that this is not my intent. I'm just pointing out what I've learned, and what scares the crap out of me.

I wouldn't think all the risks associated with FLA apply to SLA, but as you pointed out bad things can happen by accident. Suppose a pet or unknowing visitor flipped that switch or shorted out the lugs. Suppose you did that again, left for a couple hours and there no safegaurds. Ouch!

Heck the code even calls for a lockable containment enclosure, wih signs and all sorts of other stuff. I'm not up to the full compliance of the code myself, but I hope to make my system a little better and safer as I can afford to do so. I wish I could post the entire NEC as it relates to RE here for a constant reference, but man is it long and detailed!

I mentioned one point in the other thread I referenced, but will restate that here:

Suppose an fire unrelated to the batteries started in your house. When the firefighters arrive to put that blaze out and there is vaporized lead and sulphuric acid in the smoke. They are now exposed to a far greater danger than would otherwise exist. Sure they have protective gear that would help, but these chemicals would pose an extra risk they should not have to face. Also that free lead is now in the atmosphere and will settle out on something somewhere. Do we need it in our food supply, soil or water? Yes I know cars with batteries burn every day, and that is bad, but if we can avoid releasing this junk into the air I feel we should at least make an honest attempt to do so.

I'm just trying to say we need to take the precautions we can easily take and constantly be aware that there are serious dangers involved in using these batteries. It just seems like the responsible way to go, to me.

Not trying to stir up trouble,

[TomW]

Roger;

Certainly not getting under my skin. I am interested in getting good information to folks.

Cheers.

TomW

[RogerAS]

stephent,

Thanks for the response. I feel much better with a professionals' input.

Call me about the old AC gen heads and I'll set up a time to get 'em to ya.

Later,

[Ungrounded Lightning Rod]

"...Batteries should not be installed in living areas, nor should they be installed below any enclosures, panelboards, or load centers... [110.26]."

Probable reasons no doubt include (but may not be limited to):

In living areas:

 - Venting of corrosive and toxic gases into living areas is a health hazard.

 - Venting of explosive gases into living areas is a fire and explosion hazard.

 - Presence of large charged batteries in a living area is a fire hazard due to the possibility of accidental short circuits.

 - Presence of large charged batteries in a living area in case of a fire from other causes is an additional hazard due to acceleration of the fire from fire-caused shorts, release of corrosive liquids, release of corrosive and toxic fumes, etc.

Batteries are both an ignition source and a toxic/explosive fume and chemical source.  So the code wants them separated from the living area by enough space to form a firebreak and to dissipate the fumes.

Garages normally have firewalls between them and the house, and separate air circulation, due to fire risk from vehicles, water heaters, etc.  This makes them marginally acceptable.  But a separate outbuilding is far better.

So why not put the batteries and inverter nearer the mill and ship the power at line voltage from the shed to the house?

Location relative to other equipment:

 - In general load centers (i.e. breaker panels) must be unobstructed.  You must have easy access to the breakers in case you need to reset or trip them or when you must work on them.  Leaning over a bunch of charged batteries is a double hazard (especially when resetting a breaker in the dark), since dropping a panel cover, piece of wire, tool, or set of keys onto them can cause an explosion or fire.

 - Same rule gets applied to panelboards, enclosures, etc. for the same reason.  You don't want to be working over the batteries when you are diddling around with the inverter, rectifiers, instrumentation, ...  (This goes double for home-brew stuff you'll be tinkering with all the time.)

 - Also, the fumes from the batteries can corrode the electronics and breaker panel.  Bad news.  So you want them separated, with the venting leading the corrosive fumes away from the corrodible electronics.

I'd also put the batteries in the back of the shed and the electronics near the door.  The other way around might lead to being trapped if the batteries start acting up (like exploding or setting their wiring on fire) while I'm working on the panels.

[Ungrounded Lightning Rod]

It's tough ($$) to follow the NEC battery storage/use requirements and do it right.

But that cost is opposed to doing it wrong at what cost?

Well, how much are you paying for fire insurance?  If the batteries are installed not-to-code, your insurance may be voided.

• If you do have a fire you now have no house AND no payoff.  (And improperly-installed batteries increase both the risk of fire and the amount of damage if it occurs, which is why the insurance and code people want it done right.)
  
• If you don't have a fire you wasted all that premium money for no coverage.
  
  

How's that for a cost comparison?

[hydrosun]

I've installed batteries in basements, utility rooms and outside sheds. In all cases the batteries were in a sealed battery box vented to the outside.  Conduit from the inverter was lower than the vent.  And the systems pass inspection.

 It comes down to containment  of a potential hazard. Just like breakers on all wires that carry power. But I'd be just as cautious with gas lines or other high energy  dangers.

Chris

[DanG]

I've seen a Edison bank 3 tiers deep, 28-inches tall and near 30-foot long overheat - concrete walls, ceiling and floor over a foot thick heated up to over 110° F as the batteries boiled and radiated heat over a weekend in a room large enough to park two city buses in. A responding fireman tried to pry a steel vent grill out of a brick wall to improve ventilation and the facility Superintendent reminded him of the hydrogen present while he was prying and the man had to go sit down his legs got so weak.

NEC has reviewed incidents of that sort of thing for over 100 years - installations where cost really wasn't an issue still failing spectacularly. If you accept their guidelines before starting to scrounge materials things will go much smoother than attempting to retrofit a shoe-string installation. Attached picture is 200-pound aluminum battery "dog-house" enclosure I nabbed for $97 (that I really didn't have) at the local surplus and freak show store (AxeMan) but will make living with 1600 pounds of batteries easier on the ulcers...

[RogerAS]

DanG,

Nice box dude! I usually don't say that to another man, BTW. :-)

Here's the front of my Union Signal battery box. I salvaged this little(?) goodie from a Burlington Northern crossing retrofit project in South Dakota where I used to live. It weighs about 450LB, and made from some really thick steel plate throughout. I have this mounted on a concrete pad about 16" thick and with 5/8" anchor bolts. It serves the same function as it did in its first life, to store lead acid batteries. There is no lock on there at this moment, but if we leave for more than a day it is locked with a thick combo type Master. I do need to get some placards and signs pointing out the main disconnect and hazards. Like I said, I'm working on getting everything up to code, and I think I have a good start with what I have now.

Here's the inside (below), showing my bank of 6V golf carts. These are all setup for 12v+-, and the cables all feed to a set of thick copper bus bars, not shown. That's a gallon jug of distilled water and a box of baking soda I keep in there at all times on the middle shelf. The little white things on the right are pens and pencils I use to write down the specific gravity readings when I do my monthly checkups/equalization work. I keep a log of the condition of each cell and record that into a MS Works spreadsheet. I can see when the batteries begin to get weak and take action as needed. I also try to record the use of water and any other oddities. I keep my lug connections greased up and rarely see any corrosion.

This whole setup is part of my engine room/power house. Also not shown are 2 1.5" vent pipes that run to above the roof line of the powerhouse that exit from the top corner of the battery box on each side/end. Those have 2 90° elbows on top to keep rain out. I have screen mesh, nylon, on the bottom end of those to keep the bugs out. The back of the box has removeable panels with sealed edges to access the bus bars. No other euipement of any kind is inside the box. There is some junk hardware (screws/bolts/shelf brackets on the very bottom shelf that I need to get out of there. I'd love to fill up the entire box and get 24 of those 6V golf carts for a total 12V AH rating of around 2640.

Scarey story about the Edison bank! It just goes to show that batteries are indeed some dangerous "stuff" even when delt with carefully.

[Ungrounded Lightning Rod]

Cool!

I was thinking about building a shed.  But one of those would be just dandy.

Time to check the railroad salvage yards.

[RogerAS]

UGLR,

What's even cooler is that this thing had a bunch of ceramic 2 post insulators with chrome plated brass studs and nuts, like 100, inside still screwed down! There was also this giant contactor that works like new, a bunch of lightening arrestors, big caps, big resistors and all kinds of fuses and a mile of soldered eye ended multistrand copper wire. I got it for hauling it off! Getting it in and out of my Ranger pickup was a real eemmmm joy.

I still have to put the right kind and size of disconnects and other tidbits, but I keep working on it all. You guys should have seen things our first winter here where we live. What a rolling cluster XXcX!

Anyway good luck, these might still be out there in several areas. I heard they were switching over to digital switching systems and the replacement for my box hangs on a 2" steel post! These provide(d) power when, not if, the grid went down in a blizzard or  whatever. They did have big Glass Jar batteries to supply power to the line signals and telegraph repeaters and crossing lights. The rail yad guys would not sell or allow a dingle one to leave their yard. I lusted boys I truely lusted.

Later folks,

[Countryboy]

Suppose an fire unrelated to the batteries started in your house. When the firefighters arrive to put that blaze out and there is vaporized lead and sulphuric acid in the smoke. They are now exposed to a far greater danger than would otherwise exist. Sure they have protective gear that would help, but these chemicals would pose an extra risk they should not have to face. Also that free lead is now in the atmosphere and will settle out on something somewhere. Do we need it in our food supply, soil or water? Yes I know cars with batteries burn every day, and that is bad, but if we can avoid releasing this junk into the air I feel we should at least make an honest attempt to do so.

Now where am I supposed to store all of my lead ammunition?  Certainly don't want firefighters to have to encounter all that lead in a fire...

And where am I supposed to discharge all this lead ammunition?  Certainly don't want all that free lead landing anywhere...

An ounce of prevention is worth a pound of cure, but we do need to keep in mind the proper perspective of prevention and cure.  Some safety regulations can go a bit overboard.  You can live your life in a glass bubble if you wish.  As for me and my house, I am a Freedom loving American, who firmly believes that I have the right to choose what is best for my life, and what risks I am willing to accept personal responsibility for.