lightning arrester and others

[abcd]

1. Can a lightning arrester still be used after it was struck by lightning ? (you know my friend experience this in his assigned bldg.,the lightning arrester was removed due to the strong impact).

2. Which is much better an underground service entrance powerlines or aerial cabling/service entrance? (pls. explain the electrical principles behind its applicability. I know you guys are experts, so i will listen)

3. What wud be a lifespan for a hermetic type of compressor for an Air Handling Unit of 10TR?

 

[bphgravity]

Re: lightning arrester and others

1. I would think this would depend on the product performance guaranty. I would check with the manufacturer for their suggested re-use information.

2. There are obvious benefits and negatives for each method. I prefer the lateral method in that it is much more aestheticaly pleasing and prone to less damage from winds or flying/falling debry.

3. I have no clue.

 

[zog]

Re: lightning arrester and others

"1. Can a lightning arrester still be used after it was struck by lightning ? (you know my friend experience this in his assigned bldg.,the lightning arrester was removed due to the strong impact)."

A NETA testing firm can verify if the arrestor is still fit for service. Sometimes they can be reused but usually they need to be replaced.

 

[charlie]

Re: lightning arrester and others

The lightning arrester is a surge arrester. 280.2 states, "Surge Arrester. A protective device for limiting surge voltages by discharging or bypassing surge current, and it also prevents continued flow of follow current while remaining capable of repeating these functions."

The lightning arresters we use have an indication that they are bad, the bottom cap blows off so we can see that it needs to be replaced. I don't know how the lower voltage lightning arresters are designed.

Underground service conductors are better because of the ability to withstand falling tree limbs. In general, the service conductors are not damaged by lightning. However, lightning will occasionally hit an overhead service drop. On the other hand, lightning may hit the ground and the effects of the lightning on the service lateral will cause a lot of damage to a building.

 

[rattus]

Re: lightning arrester and others

AC Compressors:

My Day-Nite (Carrier) residential unit has been going for 40 years.