I had a friend who always bolts his transformers to the floor, but was questioned by another electrician whether it was necessary...we'd like to know if there is a reference in the CEC about having to bolt transformers to the floor or perhaps a building code requirement under "seismic"?

Thanks, any feedback would be appreciated!

Well we don't lean the panels against the wall either. All equipment has to be securly mounted.

The building code defines these things and in a seismic area the rules are stricter often requiring snubbers and seismic rated anchors etc.
2-118 refers us to Appendix G which are the many Building code references.

I can tell you that they must be secured but it surprises me that the rule that says so is not so easy to find and I will be looking.

26-248(1)Transformers of the dry-core open-ventilated type shall be mounted so that there is an air space of not less than 150mm between.............
26-240(4)Transformers shall be protected from mechanical damage.
I'd say either one of those covers it

I carry a hot glue gun just for the purpose of mounting transformers on the floor. It also provides mechanical protection by providing some "give" if a fork lift hits it.

I'm not advocating leaning panels against the wall, but I've seen a few transformers hung by threaded rod from the ceiling and they move quite freely. Sitting on the floor is way more secure - without glue.

The other electrician, in the original post, has a good point. Are there any rules about mounting transformers? What is secure?

If it's suspended by unistrut on threaded rod it's always bolted to the unistrut. If bolting's good enough for the hanging ones it's good enough for the floor mounted ones.

Be careful about that assumption. A transformer hanging from a ceiling might likely survive a seismic event where the one bolted to the floor does not. For example the hole that the bolt goes through can act as a bolt cutter if the hole is larger than the bolt. The side to side motion of a transformer can hammer on the bolt and shear it off. Bolts are much stronger in stretch than shear. the hanging transformer and its suspension will give in a shaker where the bolts on the floor mounted transformer shear off because it is more rigid.

Ummmm Then do you Require Large MCC sections or Switchgear to be Bolted to the Floor also?? What if its mounted on Steel Rails like a lot are in Factorys?? Do you then require it be Welded to the rails????

In California, you'd get a big fat red tag for not bolting down transformers, MCCs or switchgear......

The inspector would probably walk away shaking his head, laughing.

Then in California do they Require Gear WELDED to rails when gears set on them???
Do you know what I mean by metal rails???

When I was at GE, we'd void your warranty if you didn't bolt down the MCC, Switchboards and Switchgear.

Theres a Lotta GE gear out there thats not installed per warranty then. I never had a GE rep tell us that in fact never had any Rep tell us that.I;ll ask reps next time I see them. But been wrong before Sure I;ll be wrong again. Guess thats why we're all here right is to learn!!

What rule in California would the inspector quote when he red-tagged the job? What does the rule say? Does it specify size of bolts? Does it specify the number of bolts? Does it specify the hardness of the bolts? Are the anchors required to be of a certain material?

I looked it up its in there Buiding code.

Here's a link to the wedge anchors we generally use for anchoring in concrete.

http://www.confast.com/products/technical-info/thunderstud-anchor.aspx

As to inspections, I've never had a violation notice written up. I know better than not to bolt the equipment down.

I always tried to be up-front during my tenure as a GE Service Tech. I knew full well that the factory would do whatever it took to avoid any expenses or chargebacks.
With that being said, most of us don't like to pay for other people's shortcuts. If I install something that the end user abuses until it fails, you're darn right I'm going to try to avoid fixing it for free. Obviously if it's my fault, I'll be the first guy there in the morning to fix it at no charge. But if I didn't break it...I'm not gonna fix it for free.

I also knew that one of the ways that all companies weasel out of paying warranty claims was by saying that you didn't follow 'chapter and verse' when installing the equipment so it was your fault that the stuff broke and it's gonna be on your nickel that it gets fixed.

So when I saw someone skipping any part of the installation instructions, I let them know that this savings of a few dollars and a few hours could very easily result in an otherwise valid claim being rejected.
Most of the folks that I worked with didn't want to take the chance. They always had the final decision, but I just wanted everyone to make it with their eyes wide open.

Not quite what I meant. I'm wondering how the rule is worded. For example, could an inspector say that a .25 inch anchor is too small for a 30KVA transformer, or perhaps that 1 inch screws are too small to hold a panel on the wall?

TWH,

Read Mikesh's reply above. The same thing applies here re: shear strength.

Always "fill the mounting hole" with the anchor.

Hot glue doesn't cut it.

I have to admit that my copy of the building code is quite old. Perhaps someone can quote the rule, or at least tell me which rule it is.

I know that this great topic is old but I want to ask Twh. Did you buy new building code?

No, mersadrad, I didn't buy a new building code.

It would be very good if we had a rule about what was acceptable, but I want to know what the rule is in advance. It's never okay to have someone come by later and reject my work because it isn't what they would have done.

For example, I attach device boxes to the wall with #8 screws. They do not fill the mounting hole. No one uses 1/4 inch lag bolts to fill the mounting hole. It isn't a rule.

If there is no rule, there just is no rule. It doesn't mean that someone gets to make it up as they go along. I've been through that and I had to carry a map of which inspectors worked in each area. It sucked when one inspector went on a holiday and another inspector had a different set of rules.

By the way, when you bump old topics you have to buy everyone coffee. It's a new rule!

...coffee on me then!!!

I am sorry and and I am glad that you learned it on hard way. If you understand what I mean.

...for the old topics...I will ocationally respond some of them when I see something picking my eye. I feel better here than reading newspaper.

While I am saying this, are they any free electrical magazines what you can recomend. I know http://www.electricalline.com/ with nice virtual view ( check at the bottom ).

In CA, an inspector red tagging the equipment or plan checker would call out IBC or CaBC Chapter 16, or:

"1613.1 Scope. Every structure, and portion thereof, including nonstructural components that are permanently attached to structures and their supports and attachments, shall be designed and constructed to resist the effects of earthquake motions in accordance with ASCE 7, excluding Chapter 14 and Appendix l1A."

CaBC points to the IBC, which points to the ASCE 7, which then might point to ACI 318 for concrete, AISC 360/341 for Steel Bldgs, NDS for wood or timber construction, and ASCE 5 for CMU/Masonry structures.

It isn't as simple as calling out a particular sized bolt or screw to anchor the equipment. If enforced it requires some design.

A simple skid mtd boiler weighing about 7000lbs, requiring 8 - 5/8dia anchor bolts drilled into a concrete slab, required a 34 page structural calculation report to generate a simple note calling out 8 bolts on center in predrilled holes.

Unlike many other load problems, seismic loads are based upon the inertia generated by a mass being accelerated during a seismic event. The lateral force generated then has to be traced to the structure, to the foundation, to the soils around the structure.

For Mechanical and Electrical equipment, the lateral forces resisted are coded to be less than the bldg.

As a rule of thumb, anything over 400 lbs or above the floor by 4 ft, needs specific design calculations and detailing during design for anchorage. Technically anything weighing over 20 lbs attached to the bldg (even wall partitions) should be considered.

The codes and difficult to understand until one designs a few bldgs, and ALL structural members, but there have been some recent FEMA pubs freely available, which help in a practical fashion.

FEMA 454
FEMA e74

The explicit calculations Elec/Mech nonstructural components is generally F= [(0.4)(a)(Sds)W/(R/I)](1+2z/h), where a = 1.5, Sds is found from the USGS website for the location ,..it's the design spectral acceleration, short term, and usually ranges from 0.5 to 2.0g. W is the operating seismic weight of the equipment. R is a Response coefficient, I is an Importance factor, z is the height off the floor and h is the roof height. (each defn in the code is more explicit)

This calc provides and lateral force for a design seismic event for a piece of equipment applied at the centroid of the equipment. That lateral force will induce a moment and force upon the structure, which must be resisted along the bldg's structural path to the floor to the walls, to the columns, to the foundation, to the soil around the bldg.

There are additional detailing requirements. For example brackets holding the equipment in place need be designed so that when things fail, they do so in a fashion so people can live and the bldg doesn't suffer catastrophic failure ,...or so is the intent.

Rule of thumb, bolt one bolt to the equipment and 2 bolts to the floor at each bracket, in both directions for any 360 degree seismic motion. This way if the bolts fail, they are designed either keep the brackets attached to the equipment or to the structure.

There are a litany of other minutia,...generally, don't use powder actuated fasteners when the anchor is in tension,..violates the seismic codes.

Hospitals and schools probably have the best seismic designs in general practice, but look at the FEMA e74 for some typical examples of how to anchor equipment and examples of their failures.

PS

The only facilities really requiring such extreme design documentation are Class IV facilities,..ESSENTIAL facilities, such as hospitals, fire stations, etc.

Read the Exemptions section in Chapter 16 of the ASCE 7 if in doubt.