Main breaker in seperate enclosure

[kwired]

I don't know why you would say that. The vent is normally near the dryer receptacle and once they hack around the vent or figure the receptacle may have gotten hot they will disconnect power.

Which goes along with what I said, they first assess the situation, and when something concerns them about needing to shut power off they do it. Some FD's may be more likely to turn it off sooner then others, just depends on what their training and assessment of the situation is.

 

[kwired]

When I was a kid the house next door had a small fire in an exterior utility room and the FD was called. My dad was standing nearby when a firefighter ran up to the utility room door wielding an axe. My dad told him "Wait!" and opened the door for him.

I don't know you real well but am assuming when that happened wasn't yesterday. Even small town volunteer fire fighters I see in recent years are more "professional" and have had a lot more training then the way things were when I was a kid.

 

[ggunn]

I don't know you real well but am assuming when that happened wasn't yesterday.

You don't know me at all , but you are correct; the incident I related occurred in the mid 1950's.

 

[growler]

I know, question becomes is this possible requirement going to be for dwellings only or a general requirement for everything? Most of art 230 is general and applies to everything.

I would assume ( and that's dangerous ) that they will eliminate the loop-hole that allows for a mater base and panel to not have an outside disconnect if back to back. Already there is no clear determination if a disconnect is needed other than getting the approval of the AHJ. Some say 5 ft and others 10 ft, it's just an opinion.

Most of the houses that I work on already have an outside disconnect and have had such for the last 20 or so years. I don't see much of a change other than for small tract houses where they try to save every dollar.

I don't know if the code should require a disconnect but I prefer it to a system that blocks off the top section of the panel. For a house built on a slab we often need to fish into the top of the panel.

The disconnect seems to solve a lot of problems for a limmited cost. Even if we go back to the 1999 code cycle many homes were required to have an outside disconnect. I don't see the big deal.

 

[kwired]

I would assume ( and that's dangerous ) that they will eliminate the loop-hole that allows for a mater base and panel to not have an outside disconnect if back to back. Already there is no clear determination if a disconnect is needed other than getting the approval of the AHJ. Some say 5 ft and others 10 ft, it's just an opinion.

Most of the houses that I work on already have an outside disconnect and have had such for the last 20 or so years. I don't see much of a change other than for small tract houses where they try to save every dollar.

I don't know if the code should require a disconnect but I prefer it to a system that blocks off the top section of the panel. For a house built on a slab we often need to fish into the top of the panel.

The disconnect seems to solve a lot of problems for a limmited cost. Even if we go back to the 1999 code cycle many homes were required to have an outside disconnect. I don't see the big deal.

I have been in this trade since 1987 code was in effect, never do I remember any NEC since then requiring an outside service disconnect. You sure you didn't have a local amendment requiring that or were dealing with mobile or manufactured homes when that was an issue?

Meter location has nothing to do with any of this either - in fact NEC doesn't even require metering equipment, and in some instances there isn't one, others instances it is even after the service disconnect - like a multi-tenant application with more then six tenants.

 

[don_resqcapt19]

Don I never thought that Fire Fighters are afraid to spray water on energized electrical but they do tend to be Ax happy types and tend to open walls and ceilings the quick way.

Actually most will avoid putting water on anything that they think may be energized. As far as the use of the axe, there are valid reasons to ventilate the building and that may require the use of tools like that.

If there is no disconnect there is a chance of hitting SE cable with no overcurrent protection. Even if they just hit the neutral and a phase they may do more damage than the fire.

It would be unlikely that ventilation opening would be made near the service entrance conductors.

 

[don_resqcapt19]

I know, question becomes is this possible requirement going to be for dwellings only or a general requirement for everything? Most of art 230 is general and applies to everything.

Also will it be extended to the main disconnect for buildings supplied by feeders or just for service disconnecting means?

Now place service disconnect outdoors but in a locked fenced in area - have we accomplished much on this one?

My understanding, even though I can't find the PI (very poorly designed system in use for the change process now) was that the rule was limited to one and two family dwelling units.

This information came from a brief preview class on the 2017 code that I was at in Chicago at the Illinois IAEI winter meeting. It was explained that the 2020 effective date was to give more time for objections to the change. It may never actually appear in the 2020 code.

 

[don_resqcapt19]

When I was a kid the house next door had a small fire in an exterior utility room and the FD was called. My dad was standing nearby when a firefighter ran up to the utility room door wielding an axe. My dad told him "Wait!" and opened the door for him.

There are yahoos in every trade or occupation

 

[growler]

It is actually fairly safe to put a water stream on energized electrical equipment at dwelling unit voltages. The stream is not really solid enough to conductor a hazardous amount of current back to the fire fighter. However the standing water on the floor or the ground is conductive enough and becomes a shock hazard if the standing water becomes energized.

Actually most will avoid putting water on anything that they think may be energized.

Make up your mind.

I would assume ( and hope ) they would put out a small dryer fire with a fire extinguisher that is rated for electrical fires. I would also asume they would have a hose standing by in case there is more of a fire in the walls than can at first be determined.

So what is your point? They may or may not want to cut the power but I think we are talking about the times when they will wish to turn power off and the best ways to do so.

 

[growler]

It would be unlikely that ventilation opening would be made near the service entrance conductors.

What's that suppossed to mean anyway? All accidents are unlikely. If I kill myself by a likely method it's call suicide.

The problem you are trying to solve in the first place is unlikely. Many people work hot circuits for years and never get hurt.

If we are trying to protect against things that happen on a daily basis we can get rid of about 99 percent of the code book and safety rules.

 

[growler]

I have been in this trade since 1987 code was in effect, never do I remember any NEC since then requiring an outside service disconnect. You sure you didn't have a local amendment requiring that or were dealing with mobile or manufactured homes when that was an issue.

What you say is true and yet over simplified. Outside disconnect is not required "if" we wish to place the panel with main nearest the point of entrace of service conductors.

That's why I can go in a sub-division of 5 thoundand homes and everyone of them will have a meter main combo. The may have figured that it was more cost effective to place the panel at a better location to feed branch circuits.

I didn't make myself clear when I said required. I should have said required because of panel location ( which does give them a choice ). I kind of assumed that people would know this.

 

[growler]

Just want to pick some of the best and brightest minds (which are) on this site. What do you think about having the main service conductors and main breaker enclosed in a separate shield like those found in Canadian load centers? Do you believe there are any advantages? That they are worth mandating? Or do you believe such would be of no advantage?


http://www.schneider-electric.ca/images/pictures/news/press/homeline-lr.jpg

By the way folks this is what I'm against.

A panel that blocks the top section. I can't imagine the trouble there would be trying to fish wire into this thing. An exterior disconnect will kill all power to the panel and leave the panel free at the top.

 

[don_resqcapt19]

Make up your mind.

I would assume ( and hope ) they would put out a small dryer fire with a fire extinguisher that is rated for electrical fires. I would also asume they would have a hose standing by in case there is more of a fire in the walls than can at first be determined.

So what is your point? They may or may not want to cut the power but I think we are talking about the times when they will wish to turn power off and the best ways to do so.

MY two statements are not in conflict....while it is fairly safe to put water on an electrical fire at dwelling unit voltages, most fire fighters will avoid doing that.

If the fire involves the structure, they will want to kill the service. For an appliance fire they will also likely kill the service, but only because that is easier to do than locate the actual breaker that provides the power to the appliance.(few dwelling unit panels are actually labeled as required by the code).

As far as putting out an electrical fire, there is no extinguisher that can do that...there is only one way to put out an electrical fire and that is to remove the source of power. Extinguishers rated for electrical fires just mean that the agent is non-conductive, but the only thing they put out are the combustible materials that are burning. In many cases the use of a dry agent will do more damage than if you used water, but like I said, most will avoid putting water on energized electrical equipment.

 

[don_resqcapt19]

...
It would be unlikely that ventilation opening would be made near the service entrance conductors.

What's that suppossed to mean anyway? All accidents are unlikely. If I kill myself by a likely method it's call suicide.
....

What that means is that most ventilation openings are made in the roof and not on a side wall where the unprotected service cable is run. Side wall ventilation is most often accomplished by taking out windows.

Openings will be made in a side wall if the wall itself is on fire, but in that case the additional damage that would be caused by accidental damage to the service entrance conductors would be very small compared to the total damage. They would also likely wait for the utility to kill the service at the source before cutting near the service entrance conductors.

 

[growler]

As far as putting out an electrical fire, there is no extinguisher that can do that...there is only one way to put out an electrical fire and that is to remove the source of power.

Have you ever seen anything close to an electrical fire at 250V on a 30 amp breaker ( dryer set up)?

What's going to be burning is wire insulation and lent from clothing and may building materials.
These can be put out with an extinguisher.

What you are calling an electrical fire is arcing. It's a problem if near combustible materials. The best thing that can happen if for the arcing wires to touch and trip the circuit breaker.

 

[don_resqcapt19]

Have you ever seen anything close to an electrical fire at 250V on a 30 amp breaker ( dryer set up)?

What's going to be burning is wire insulation and lent from clothing and may building materials.
These can be put out with an extinguisher. ...

That is exactly what I said in my post.

Extinguishers rated for electrical fires just mean that the agent is non-conductive, but the only thing they put out are the combustible materials that are burning.

 

[growler]

I would assume ( and hope ) they would put out a small dryer fire with a fire extinguisher that is rated for electrical fires.

Extinguishers rated for electrical fires just mean that the agent is non-conductive, but the only thing they put out are the combustible materials that are burning.

Again, what are you trying to say?

I would assume that they will use an extinquisher rated for electrical. That what I said and I'm sticking to it.

 

[jumper]

My understanding, even though I can't find the PI (very poorly designed system in use for the change process now) was that the rule was limited to one and two family dwelling units.

This information came from a brief preview class on the 2017 code that I was at in Chicago at the Illinois IAEI winter meeting. It was explained that the 2020 effective date was to give more time for objections to the change. It may never actually appear in the 2020 code.

Found this:

http://www.nfpa.org/newsandpublications/nfpa-journal/2016/march-april-2016/in-compliance/nfpa-70

It talks about the PI.

I may try the durn NFPA Terra View website later and see what I can find.

 

[jumper]

Found this:

http://www.nfpa.org/newsandpublications/nfpa-journal/2016/march-april-2016/in-compliance/nfpa-70

It talks about the PI.

I may try the durn NFPA Terra View website later and see what I can find.

Found it: Public Input No. 4224-NFPA 70-2014

(1) Readily Accessible Location.
The service disconnecting means shall be installed at a readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors.

( A ) Where installed on one family and two family dwellings, the service disconnecting means shall be installed outside the structure at the nearest point of entrance of the service conductors.

Statement of Problem and Substantiation for Public Input
Statement of Problem

Access to the service disconnecting means for first responders is very challenging when the disconnect is installed in a basement. Additionally with the incorporation of distributed generation such as PV or energy storage devices, the lack of access to safely securing the power generation to a residence from the exterior is made even more challenging.

The installation of a utility external service disconnect is a common practice in many areas of the country, including corrosive coastal environments, and should be provided in the code to ensure the safety of first responders when service disconnection is required in an emergency

This proposal seeks to require the installation of a utility external AC disconnect at the location of the meter on the exterior of the structure.
Submitter Information Verification
Submitter Full Name: Matthew Paiss
Organization:
Affilliation: International Association of Fire Fighters
Street Address:
City:
State:
Zip:
Submittal Date: Thu Nov 06 15:09:10 EST 2014

Committee Statement
Resolution: This requirement is onerous and not necessary. The hazard in a one or two family dwelling than it is not greater than in a multi-family dwelling or commercial building. The statement relative to environmental impact on exterior service disconnects is incorrect and in fact there are many instances where exterior disconnects do not operate when utilized due to the effects of the atmosphere on the disconnect. The submitter has not presented and factual data to support this requirement. Onsite power production sources have their own requirements relative to disconnecting means, anti-islanding features and proper placarding and notification relative to their presence on the property.

 

[jumper]

I will look for the comments on that PI later.