Fused disconnect required

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david said:
Correct suitable for use as service equipment, so we agree, it needs to have local protection, overload / over current protection.
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The breaker in the panel feeding the disco is fine. The disco is being fed with protected feeder.

If this was the service disconnecting means with service conductors than OCPD would need to a part of it or adjacent to.
 
codequestion said:
Panel or switch in the trailer has to have main circuit breaker or fuse.

The engineer does not show trailor panel just disco non fused.

So the nonfuse disco outside on rack next to trailer has to be service rated but panel inside the trailer has to have main overcurrent protection.

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Yep. For this install an unfused disco will work, but panel inside needs a main or a fused disco inside for the pane.
 
jumper said:
The breaker in the panel feeding the disco is fine. The disco is being fed with protected feeder.

If this was the service disconnecting means with service conductors than OCPD would need to a part of it or adjacent to.
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Unless this is a change from 2008 that i am not seeing than the local disconnect has to have no more than six throws of the hand, and incorporate a fuse or circuit breaker the same as if it was a service disconnect.

Everything that i read on the change in 225.36 2011 NEC has to do with that, article 550 does not have that change as seen in 225.36
 
jumper said:
Yep. For this install an unfused disco will work, but panel inside needs a main or a fused disco inside for the pane.
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This discussion has come up multiple times on this site in the past and has always been said that the local disconnect has to have protection locally not just at the service location
 
david said:
Unless this is a change from 2008 that i am not seeing than the local disconnect has to have no more than six throws of the hand, and incorporate a fuse or circuit breaker the same as if it was a service disconnect.

Everything that i read on the change in 225.36 2011 NEC has to do with that article 550 does not have that chnge as seen in 225.36
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Why would the disco need fuses, what would they protect?

Disco is fed from feeder?
 
david said:
This discussion has come up multiple times on this site in the past and has always been said that the local disconnect has to have protection locally not just at the service location
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I see nothing in 550.11(A) requiring that.

If this were the actuall service disconnect, than (B) would require that it follow 230 and OCPD at the disco would be needed.
 
Lets throw another fly in the ointment.... IF it is a Art 550 application (I missed if we confirmed that), 550.31 says mobile homes must be supplied by 120/240. Does not appear 208 is acceptable.
 
jumper said:
Why would the disco need fuses, what would they protect?

Disco is fed from feeder?
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That is not the question, the question is does the code require it or not. There is no change in this from previous code cycles, so what has changed . What does suitable for use as service equipment mean

NEIS Nation electric institute standards
"So four (4) important characteristics of service equipment are:"
1. It must be equipped with a single means of disconnect (main) or not more than six switches or circuit breakers in the same enclosure.
2. It will typically have a minimum and maximum short-circuit current rating. This rating is typically in thousands of amperes.
3. The equipment will also be provided with grounding and bonding capabilities typically in the form of a main bonding jumper in accordance with 250.28.
4. In larger panelboards and switchboards that are suitable for use as service equipment, there will usually be a neutral disconnect link provided to meet the requirements in 230.75. The purpose of the neutral disconnecting link is for testing. This link can be used to determine that there are no “neutral-to-ground connections on the load side of the service disconnecting means. This testing is typically performed with the system de-energized.
 
jumper said:
I see nothing in 550.11(A) requiring that.

If this were the actuall service disconnect, than (B) would require that it follow 230 and OCPD at the disco would be needed.
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I do not see disconnect 13 as in the mobile home but if it is not the local disconnect than one needs to be provided outside with in 30 feet if it is in the mobile home than 550.11 (A)

550.11 Disconnecting Means and Branch-Circuit Protective Equipment.
(A) Disconnecting Means. A single disconnecting means shall be provided in each mobile home consisting of a circuit breaker, or a switch and fuses and its accessories installed in a readily accessible location near the point of entrance of the supply cord or conductors into the mobile home
 
david said:
That is not the question, the question is does the code require it or not. There is no change in this from previous code cycles, so what has changed . What does suitable for use as service equipment mean

NEIS Nation electric institute standards
"So four (4) important characteristics of service equipment are:"
1. It must be equipped with a single means of disconnect (main) or not more than six switches or circuit breakers in the same enclosure.
2. It will typically have a minimum and maximum short-circuit current rating. This rating is typically in thousands of amperes.
3. The equipment will also be provided with grounding and bonding capabilities typically in the form of a main bonding jumper in accordance with 250.28.
4. In larger panelboards and switchboards that are suitable for use as service equipment, there will usually be a neutral disconnect link provided to meet the requirements in 230.75. The purpose of the neutral disconnecting link is for testing. This link can be used to determine that there are no “neutral-to-ground connections on the load side of the service disconnecting means. This testing is typically performed with the system de-energized.
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SUSE is determined by the marking of 230.66 requirements.

I see nothing in 550.32 (A) requiring OCPD at the trailor disco. OCPD for the disco and feeder is at the service panel.
 
david said:
I do not see disconnect 13 as in the mobile home but if it is not the local disconnect than one needs to be provided outside with in 30 feet if it is in the mobile home than 550.11 (A)

550.11 Disconnecting Means and Branch-Circuit Protective Equipment.
(A) Disconnecting Means. A single disconnecting means shall be provided in each mobile home consisting of a circuit breaker, or a switch and fuses and its accessories installed in a readily accessible location near the point of entrance of the supply cord or conductors into the mobile home
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The 13 disco is just outside trailor. Does not satisfy 550.11, I said that to OP.
 
Hey CQ, get back here! I ain’t done yet, we gotta talk about 550.33.

I have a few questions about this here feeder.......:D

Did we get into 250.32, if not....grounding is another thing that comes into play here.

Having fun yet?:)
 
jumper said:
SUSE is determined by the marking of 230.66 requirements.

I see nothing in 550.32 (A) requiring OCPD at the trailor disco. OCPD for the disco and feeder is at the service panel.
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Ok, so he is looking for a non-fused, insulated neutral, safety switch, and according to UL Marking Guide suitable for use as service equipment , with the appropriate ground fault interrupting rating

So in the real world He is looking for a fused disconnecting means
 
Just to the OP

I do not know if this is applicable in your install. But it has been my experience, with some JOB site type mobile homes with some of the HVAC units are intended to be connected from the exterior panel in your case the location of the exterior disconnecting means that is 80 or so feet from the service location.

It may be worth considering installing a small panel giving you a means to take care of any exterior equipment at the trailer site

If you 120/208 volt trailer is site specific it may not be of any concern, all the equipment may be feed from the trailers interior distribution panel
 
david said:
Ok, so he is looking for a non-fused, insulated neutral, safety switch, and according to UL Marking Guide suitable for use as service equipment , with the appropriate ground fault interrupting rating

So in the real world He is looking for a fused disconnecting means
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The neutral merely splices through, it is not the service disconnecting means here, neutral does not have to be terminated.

They make this switch.

Is it expensive, yes. ~$1000.00 for 100A 3P.

Are there cheaper alternatives, yes-usually involves fuses.:)

But per code, fuses would not be required for the given parameters here.

This was an exercise to learn how to use the NEC, not how to spec equipment wisely.
 
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jumper said:
Why would the disco need fuses, what would they protect?

Disco is fed from feeder?
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jumper said:
The neutral merely splices through, it is not the service disconnecting means here, neutral does not have to be terminated.

They make this switch.

Is it expensive, yes. ~$1000.00 for 100A 3P.

Are there cheaper alternatives, yes-usually involves fuses.:)

But per code, fuses would not be required for the given parameters here.

This was an exercise to learn how to use the NEC, not how to spec equipment wisely.
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Has repeatedly been mentioned the disconnecting means (the one required within 30 feet of the "trailer") must be suitable for use as service equipment - even if not installed as a "service disconnecting means".

How many items can you find that are "suitable for use as service equipment" that don't either contain overcurrent protective devices or at very least require additional overcurrent protection devices. When the device is a non fused safety switch - that would require additional overcurrent protection - most of those I have seen (especially if used on service conductors, though in this case are used on a feeder) require fuses as the protection. Can we disregard the fuse requirement here since this is a feeder as long as the available fault current doesn't present an issue with the switch rating? Many non fused safety switches are only rated 10kAIC unless protected with fuses. That said I bet the available fault current at OP's disconnect location is less then 10kA anyway.
 
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