210.4b for 517 type installations...

[JHooser]

Hello All,

Anyone else see 210.4b as being an issue on the emergency system side of things for Hospitals and Nursing Homes? I would have a problem with someone plugging something into a red plug that they shouldn't and it taking down several plugs in several rooms some of which could have resporators or some other type of life support equipment. I think I may just have to require a separate nuetral be run for all circuits on the emergency side to avoid this issue. Just wanted to know if anyone has raised this question since I could not find anything by searching the forums.

Jonathan Hooser

 

[Hendrix]

Hello All,

Anyone else see 210.4b as being an issue on the emergency system side of things for Hospitals and Nursing Homes? I would have a problem with someone plugging something into a red plug that they shouldn't and it taking down several plugs in several rooms some of which could have resporators or some other type of life support equipment. I think I may just have to require a separate nuetral be run for all circuits on the emergency side to avoid this issue. Just wanted to know if anyone has raised this question since I could not find anything by searching the forums.

Jonathan Hooser

maybe art. 708 would be good to look at.

 

[JHooser]

I can see COPS being something viable for the Hospital sector, even though it is an increased cost as compared to 517. The limited care facilities are where I do not think I could use this section.

The main reason that I heard for this 210.4b section was because of the shock hazard posed by personnel working on the wiring device. Is this the only reason for it?

 

[raider1]

The main reason that I heard for this 210.4b section was because of the shock hazard posed by personnel working on the wiring device. Is this the only reason for it?

Yes, the reason that 210.4(B) was put into the 08 NEC was to help mitigate the hazards that exist when working with multiwire branch circuits.

By the way welcome to the forum.

Chris

 

[JHooser]

Yes, the reason that 210.4(B) was put into the 08 NEC was to help mitigate the hazards that exist when working with multiwire branch circuits.

By the way welcome to the forum.

Chris

Thanks Chris! Been browsing for a few years and figured it was time to register since I will sit for my PE exam this year.

Hmmm. I wish they would have just stated to label the multiwire circuit properly so that they could shut them down when service is required instead of tying the circuits together so that if one trips they all trip. It's an inconvenience, but I could live with it on the normal side. Just seems like it could cause some issues on the emergency side of things.

 

[bobsherwood]

Jonathan, It was pointed out to me in an earlier discussion on this..... You do not have to use a two pole or three pole breaker. You may use single pole breakers with "an identified handle tie". This being the case, one breaker tripping will probably not have force enough to turn off the other one or two... Makes better sense to me to tie single pole breakers together. I am not liking this new rule...

 

[JHooser]

Jonathan, It was pointed out to me in an earlier discussion on this..... You do not have to use a two pole or three pole breaker. You may use single pole breakers with "an identified handle tie". This being the case, one breaker tripping will probably not have force enough to turn off the other one or two... Makes better sense to me to tie single pole breakers together. I am not liking this new rule...

Interesting. I guess I need to call up my rep and see if I can get a sample of this tie. I did not realize that one breaker could trip without tripping the rest. If that is the case then that would alleviate most of my concern here. I would just have to specify those specifically for this use on the projects. Thanks for the replies.

 

[MNWildcat]

Jonathan, It was pointed out to me in an earlier discussion on this..... You do not have to use a two pole or three pole breaker. You may use single pole breakers with "an identified handle tie". This being the case, one breaker tripping will probably not have force enough to turn off the other one or two... Makes better sense to me to tie single pole breakers together. I am not liking this new rule...

Yes, but to reset the tripped breaker, the other two have to be turned off. Still not a good design. We do lots of healthcare projects and with the new code our standard is separate neutrals with each line. It is extra copper, but tying three lines together is not practical. Even in non-healthcare we run the extra neutrals. Especially for lighting, you would take down a large area to reset one CB.

 

[bobsherwood]

The breaker ties are removable. Still, I see your point in keeping the circuits separate. I really do not understand this code addition.

 

[augie47]

A nunber of contrators and engineers I have talked with are moving toward seperate neutrals to avoid a host of problems associated with 210.4(B).
As a side note, my experience has been that breakers connected with handle ties tend to turn off in conjunction with any tied breaker that trips.

 

[JHooser]

Yes, seems like I will just have to run separate neutrals. I can still run multiple circuits with separate neutrals in the same pipe with out tying the breakers together, correct?

 

[roger]

I can still run multiple circuits with separate neutrals in the same pipe with out tying the breakers together, correct?

Absolutely but, you have to consider they are current carrying conductors now and must be figured in as far as derating purposes, of course this shouldn't affect wire size until after you have 9 CCC's in a conduit.


BTW, the 210.4 rule is stupid IMO.

Roger

 

[JHooser]

Awesome, I figured fill rates and derrating would be needed. Sounds like more money, I am sure my clients are going to love that. Thanks again guys for the responses. I think I am going to put a bee in the ear of the State Nursing home peeps here in Texas about the impact to the emergency side for this. Maybe it will help, but then again maybe not.