Electrical Safety

I keep getting calls about bonding metal gas piping from contractors who tell me that the inspector is telling them to bond the gas system to the grounding electrode conductor or the grounding electrode, and they want to know if it is OK.  Those are two of the methods that are permitted to be used but they are not the only ones you can use.  In 250.104 B (1) allows the equipment grounding conductor from the branch circuit that is feeding the gas appliance to be used and that would be all you would have to use no other Bonding required.  See the slide below where a branch circuit is feeding a gas heater in an air handler.  This circuit could be for the fan motor or the gas restrike it doesn’t matter as long as it has an equipment grounding conductor.  Note that the section states any of the following methods 1 through 5.

Till next time be safe work safe

Jake

This week we will look at the location for one on each level.  Florida Building Code Residential section R314.3 (3).

R314.3 Location. #3

Smoke alarms shall be installed in the following locations:

3.On each additional story of the dwelling, including basements and habitable attics and not including crawl spaces and uninhabitable attics. In dwellings or dwelling units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level.

Till next time be safe work safe

Jake

In the next couple of weeks we will examine the placement of smoke alarms in dwelling units.

NFPA 72 2013 edition

29.5.1.1* Where required by applicable laws, codes, or standards for a specific type of occupancy, approved single-and multiple-station smoke alarms shall be installed as follows:

(1) In all sleeping rooms and guest rooms

(2) Outside of each separate dwelling unit sleeping area, within 6.4 m (21 ft) of any door to a sleeping room, the distance measured along a path of travel

FBC 2017 Residential Code

R314.3 Location.

Smoke alarms shall be installed in the following locations:

1.  In each sleeping room.

2.Outside each separate sleeping area in the immediate vicinity of the bedrooms.

Although they seem to have the same information the NFPA 72 version goes into further detail as to the location on the outside of each bedroom.  21’ is how close to the bedroom the smoke alarm is required.  So you could cover more than one bedroom with a single alarm where you have grouped bedrooms.

The alarm in the picture on the left could cove additional bedrooms if they are within 21’.

Till next time be safe work safe.

Jake

Click on the picture to get a full screen version.

This weeks column is not about a Code change it is about a common problem we all face on a regular basis.  Footer steel, when is it required to be made part of the Grounding Electrode System?  We will have to check with the building plans examiner or the building inspector and see if there is going to be steel in the footer and if it will need to be made into a Grounding Electrode?

What will require it to be made into a concrete-encased electrode.  There are three requirements to make a good concrete–encased electrode.  The first is that the rod be at least 20’ in length, and it does not have to be one 20’ piece, it can be several shorter pieces connected together to make a 20’ piece.  The second is that it has to be at least a 1/2” in diameter. and the third and probably the most important is that it cannot be isolated from the Earth by a vapor barrier.

We are creating another electrode for our Grounding System.  In section 250.50 they talk about the Electrode being present.  What do we do when it is already poured. I get calls all the time about what to do when they miss the steel in the footer.  At that point I feel that the steel is not available and although you may want to chip into a footer to find a piece of steel rebar how do you know if it is 20’ long, and is not above a vapor barrier?  I have spent time trying to come up with a solution, because chipping into a slab is probably not the best answer. You could cause cracks in the concrete by hitting and vibrating the steel rebar when chipping into the footer.  So when someone calls me in the future and they ask what to do, my solution will be to get them to dig a trench and lay a 20’ piece of 1/2” rebar and make a connection to it and then encase it in at least 2” on concrete.  Maybe next time they will remember to connect the steel and call for an inspection. 

We just need to train the General Contractors and the Electrical Contractors that if this steel if available it is required to be part of our Grounding Electrode System.  If the building plans don’t call for steel in the footer we cannot make them put it in.  It is only required when there is steel and the footer has no vapor barrier and is called out for on the  plans.

Till next time be safe and work safe

Jake

This weeks photo comes from Mike Dinorscio in Boca Raton.  Thanks Mike

And you wonder why we have inspectors!

Got a great photo send it to me at jleccemail@hotmail.com

Jake

This weeks information is not a Code Change but a clarification.  When can Service Conductors be mixed with Feeders? The answer is NEVER!!

Till next week work safe be safe

Jake

I get a lot of questions on how Table 310.16 work with the three temperature columns, and the terminations of these conductors.  Square D – Schneider Electric has a technical guide to how these sections are applied to the terminations of conductors. See the attached link for information on this very often misunderstood section of the Code.  Jim Pauley the author has been a great asset to the electrical industry for over 25 years.  He often takes on the most controversial sections of the Code and explains them in a way that even a novice in our trade would understand.

Till next time work safe, be safe.

http://static.schneider-electric.us/docs/Power%20Management/0110DB9901.pdf

Send in your questions , we will find an answer.

Jake

Although this is not a code change it is very important to understand the requirements of this section.

I know we where looking at the one of most violated section of the code 110.26 Spaces About Electrical Equipment several months back and I would like to continue on with that section and examine the safety factors built into these minimums.  There are several clearances that come into play when placing equipment for an electrical installation.  The first is the obvious one of being able to walk up to a panel or some other piece of equipment and service or examine it.  Directly in front of a panel is a minimum of 3’.  That 3’ is the absolute minimum and nothing less, this gives you a quick escape incase something happens and it blows up or shorts out , that 3’ gives you a chance to escape.  I don’t know how equipment can be left with any measurement less than 3’ because it is your life and safety that is the reason for this requirement.  The crews that I work with have come to understand the minimum working clearance in front of equipment, and how important it is, and the reasons behind the requirements of the code.  So over the next couple of weeks and months I will try to examine the clearances and what the minimums are, and why they are so important. 

One of the best teaching tools I have found in the last ten years is my camera and the pictures it takes in order to document our quest for a safer electrical installation. Showing you what I find and how to correct it, is better understood than telling you that you violated a section of the Code. 

I know it has been a while since I have posted anything but my transition back into the private sector has take more time than I thought it would, so I hope to be back on track now that I have settled in to my new job.

  Till the next time, work safe, be safe

Jake

Former Chief Electrical Inspector WPB

Sizing a gutter for the proper fit is relatively easy.  I get a lot of calls to make sure that the gutter that they are using is up to code. 

We are allowed by code to fill a gutter to 20%. of its interior cross-sectional area (366.22(A),(B))  This is for both sheet metal and Nonmetallic gutters

Figuring the 20% is easy, for example.

If you have a 6 X 6 gutter, that would have total of 36 sq. in. and 20% of that is 7.2 sq. in. (36  X  20%  =  7.2 sq. in.) of space to use.  Table

5 is used for the area per conductor.  Take a 3/0 THWN conductor it is listed at .2679 sq. in.for each.  if you wanted to know how many could be

used in a 6  X  6 gutter, you can take the 7.2 sq. in. and   divide it by .2679 to get the maximum number that would be allowed to be installed in

that gutter.  7.2  /  .2679  =  26 conductors. 

You would also have to check the wire bending space minimum from Table 312.6(A). which would require a minimum of 4’” for a 3/0 conductor.

Till next time, work safe always check the circuit with a tester.