PPE for turning on 480v service?

[wireguru]

Here is the situation:
industrial park built in the early 1980s. Each unit has a 200a 480v 3ph service. I dont know the size of the main, lets say its 1200 amps. I havent seen the gear, dont know its make or whether the main for each unit is a breaker or fused switch.

the property owner has not had an arc flash study performed.

what would the procedure be to turn on the service to one of the units after it had been turned off. Knowing the available fault current is going to be high, its 480v, the switchboard hasnt really been touched since it was put in, it seems as though people (building owner and tenants) shouldnt be just opening and closing these mains.

(im not doing any of this work, it was something I observed and was wondering what the procedure would be)

any thoughts?

 

[zog]

Here is the situation:
industrial park built in the early 1980s. Each unit has a 200a 480v 3ph service. I dont know the size of the main, lets say its 1200 amps. I havent seen the gear, dont know its make or whether the main for each unit is a breaker or fused switch.

the property owner has not had an arc flash study performed.

what would the procedure be to turn on the service to one of the units after it had been turned off. Knowing the available fault current is going to be high, its 480v, the switchboard hasnt really been touched since it was put in, it seems as though people (building owner and tenants) shouldnt be just opening and closing these mains.

(im not doing any of this work, it was something I observed and was wondering what the procedure would be)

any thoughts?

You would refer to the NFPA 70E task tables, but you need to knwo the availble fault current and clearing time to know if the tables can be applied. But, typically for a small service of 1200A you would expect to be in the limits of the tables.

 

[jim dungar]

I would never expect service entrance equipment to meet the notes of the tables, utility protective devices will almost never open fast enough.

 

[zog]

I would never expect service entrance equipment to meet the notes of the tables, utility protective devices will almost never open fast enough.

Maybe I am wrong here but in an industrial park I am used to seeing each building fed from a small padmout transformer with a fused seconday, but I can guess this varies by region and vintage. I don't deal with smaller systems like this and am only basing this on the industrial parks the companies I have worked for resided.

Your experience differnt with industrial parks?

 

[jim dungar]

Maybe I am wrong here but in an industrial park I am used to seeing each building fed from a small padmout transformer with a fused seconday, but I can guess this varies by region and vintage. I don't deal with smaller systems like this and am only basing this on the industrial parks the companies I have worked for resided.

Your experience differnt with industrial parks?

There is not a single major utility, in WI, MN, SD, ND, or IL, that provides transformers with 'fused secondaries'.

 

[zog]

There is not a single major utility, in WI, MN, SD, ND, or IL, that provides transformers with 'fused secondaries'.

Maybe they are owned by the industrial park, the fuses are not part of the transformer but are in an adjacent switch. Pretty sure I have some photos somewhere.

 

[wireguru]

around here theyre usually a padmount (or 3 cans in a vault or cage) then in the building electrical room a switchgear lineup with a main fused or breaker, and individual meters and main breakers for each unit.

 

[brian john]

around here theyre usually a padmount (or 3 cans in a vault or cage) then in the building electrical room a switchgear lineup with a main fused or breaker, and individual meters and main breakers for each unit.

With utility protection only on the Primary.

 

[jim dungar]

... the fuses are not part of the transformer but are in an adjacent switch.

Then the separately mounted fused switch is probably the service entrance equipment.
I cannot believe a utility would want to take responsibility for LV fuses and switch maintenance without a 'special' agreement.

 

[wireguru]

Then the separately mounted fused switch is probably the service entrance equipment.
I cannot believe a utility would want to take responsibility for LV fuses and switch maintenance without a 'special' agreement.

these services dont have any OCP at the transformer secondary. At this property the primary comes to a pole on the property where they go underground over to the transformer. This pole has a switch and fuses on it. The switchboard has fuses or a CB. couldnt see it as someone had broken their key off in the lock of the power room :roll:

im just trying to find out what is necessary to safely turn this thing on, aparrently it has been off for some time. property owner is no help 'just turn it on, it worked fine for the last tenant' power company will set the meter but wont turn the main on.

 

[zog]

these services dont have any OCP at the transformer secondary. At this property the primary comes to a pole on the property where they go underground over to the transformer.

Then you need to contact the utility to get the availabel fault current to see if the tables can be applied. But as Jim stated your clearing time will likely exceed the table limits anyways, which mean you need to do an arc flash analysis.

This pole has a switch and fuses on it. The switchboard has fuses or a CB. couldnt see it as someone had broken their key off in the lock of the power room :roll:

And if there is an emergency how does one get in the room?

im just trying to find out what is necessary to safely turn this thing on, aparrently it has been off for some time. property owner is no help 'just turn it on, it worked fine for the last tenant' power company will set the meter but wont turn the main on.

If it has been idle for a long period of time I highly recommend testing the main gear before energizing.

 

[wireguru]

Then you need to contact the utility to get the availabel fault current to see if the tables can be applied. But as Jim stated your clearing time will likely exceed the table limits anyways, which mean you need to do an arc flash analysis.

And if there is an emergency how does one get in the room?

If it has been idle for a long period of time I highly recommend testing the main gear before energizing.

the broken key thing happened the day i was there (we're looking at taking this space thats how I ended up in this) and was to be dealt with by the owner that day.

i dont need to do an arc flash analysis, the property owner does, but doesnt seem to want to because 'this has been here 30 years and never had a problem. why should i have to do this when we havent changed anything'

the main gear has not been idle, just the 200a feed to this one unit has been off for supposedly a couple years.

i am trying to figure out what an EC is going to have to do to turn this on so i know what im in for as far as cost.

 

[zog]

i dont need to do an arc flash analysis, the property owner does,

That is correct, and what I meant to say

but doesnt seem to want to because 'this has been here 30 years and never had a problem. why should i have to do this when we havent changed anything'

Well the equipment is required to be labeld with at least the Ei or the required PPE, not just for turning it on, but because he owns the equipment.

the main gear has not been idle, just the 200a feed to this one unit has been off for supposedly a couple years.

Still I would at least megger it.

i am trying to figure out what an EC is going to have to do to turn this on so i know what im in for as far as cost.

Do a little testing to ensure it is safe to energize, suit up, turn it on. Less than an hour labor.

 

[weressl]

the broken key thing happened the day i was there (we're looking at taking this space thats how I ended up in this) and was to be dealt with by the owner that day.

i dont need to do an arc flash analysis, the property owner does, but doesnt seem to want to because 'this has been here 30 years and never had a problem. why should i have to do this when we havent changed anything'

the main gear has not been idle, just the 200a feed to this one unit has been off for supposedly a couple years.

i am trying to figure out what an EC is going to have to do to turn this on so i know what im in for as far as cost.

Because that is the CURRENT OSHA requirement.

 

[ZZDoug]

i dont need to do an arc flash analysis, the property owner does, but doesnt seem to want to because 'this has been here 30 years and never had a problem. why should i have to do this when we havent changed anything'

Can you say LIABILITY boys and girls? If thats how he feels just show him where the main disconnect handle is and leave. On second thought, if he ends up dead even that would get you sued. This brings to mind the old saying about knowing when to hold em and knowing when to fold em.

 

[wireguru]

Can you say LIABILITY boys and girls? If thats how he feels just show him where the main disconnect handle is and leave. On second thought, if he ends up dead even that would get you sued. This brings to mind the old saying about knowing when to hold em and knowing when to fold em.

we're not an EC working on this, we're a prospective tenant and I was seeing what we're in for to get the power turned on.

 

[ZZDoug]

I see. Not sure if an arc flash analysis is necessary if you are a tenant doing the work yourself, for a contractor though the liability issues can be huge if they dont do things by the book. But the exact tests required would depend on the equipment involved, like motors for example. But at bare minimum you would want to meg everything out, that would be the main thing. How long that would take would, again, depend on the equipment involved, but its not hard to do.
If you are wanting a contractor to take care of it though, they may end up having the same opinion of your future landlord as I do........