240.50 "and" or "or"

[iwire]

Can we feed a 30 amp 240 volt dryer from two plug type fuses.

Here is the relevant code section, what I do not understand is if we need to meet both requirements of 1 and 2 or do we only have to meet 1 or 2.

240.50 General.
(A) Maximum Voltage. Plug fuses shall be permitted to be used in the following circuits:

(1)Circuits not exceeding 125 volts between conductors

(2)Circuits supplied by a system having a grounded neutral where the line-to-neutral voltage does not exceed 150 volts

Thanks, Bob

 

[jimwalker]

Re: 240.50 "and" or "or"

i think your ok on #2
i think it's an OR

 

[electricman2]

Re: 240.50 "and" or "or"

I am going to stick my neck out and say 1 and 2. I say this because of the language of 240.51(A) which limits plug fuses to 125V. On a 240 volt circuit, when fuse blows, voltage across it will be 240V. OK, somebody get the axe.

 

[jimwalker]

Re: 240.50 "and" or "or"

240.50
(A) Maximum Voltage.Plug fuses SHALL be permitted to be used in the following.

I might be wrong but i think it is giving us a list of circuits it's ok to use them on.
#2 is what he has
Yes i see some danger but it seems to gave us the ok
If they had said must meet all the following then i would say use 1 and 2

[ September 08, 2004, 10:05 PM: Message edited by: jimwalker ]

 

[charlie b]

Re: 240.50 "and" or "or"

It is an ?or,? and the language leaves no doubt or room for interpretation. Why say I so? Because of the single letter ?s? that appears at the end of the word ?circuit,? causing the word to change into its plural form, ?circuits.?

That use of the language tells us that the two things that follow, thing 1 and thing 2, are different circuits. If they had intended a single circuit to possess both qualifications, they would have said,

(A) Maximum Voltage. Plug fuses shall be permitted to be used in any circuit {singular} that meets the following criteria:

(1) The circuit {again, singular} shall not exceeding 125 volts between conductors
(2) The circuit {and once again, singular} shall be supplied by a system having a grounded neutral where the line-to-neutral voltage does not exceed 150 volts

 

[charlie]

Re: 240.50 "and" or "or"

I agree with Charlie. It is interesting, as long as I have been on panel 10, I do not remember anyone questioning that section or making a proposal to clarify the language.

 

[iwire]

Re: 240.50 "and" or "or"

Thanks all who responded, I was leaning the direction of "or" but some other knowledgeable people did not agree. It seemed prudent to ask.

Originally posted by charlie:
I do not remember anyone questioning that section or making a proposal to clarify the language.

Bob

 

[jimwalker]

Re: 240.50 "and" or "or"

In some of them OLD panels we had 2 set of pullout cartridge fuse ,one for the range and one for the bus bar.What would be differant as to safety if one range fuse had blown ?

 

[electricman2]

Re: 240.50 "and" or "or"

we had 2 set of pullout cartridge fuse ,one for the range and one for the bus bar.What would be differant as to safety if one range fuse had blown ?

Jim, these cartridge fuses are rated for 250V. Since everyone seems to agree that it is OR and not AND I will go along with that but 240.51(A) limits plug fuses to 125V. Thier use on a 240V circuit would be a violation unless I am missing something.

 

[charlie]

Re: 240.50 "and" or "or"

Was I the first not to understand this?

No, you have not made a proposal and neither has anyone else. I suspect no one has voiced any confusion. It is sort of like a class where someone doesn't understand something but doesn't ask since everyone did understand. After the class, that person can't find anyone to explain it to him because no one else understood it either.

In the past, it was very common and acceptable to run a 120/240 volt, single phase circuit to a small fused disconnect and then to the new fangled electric clothes dryers. For what it is worth, it is still acceptable except now, you are required to use type S fuses and fuse holders (Fusestats).