Electrical component mounting panel material

[cw8]

I'm coming from the van/RV world and, in that community, there seem to be a lot of different approaches and opinions on what to mount electrical equipment (inverters, chargers, MPPT, bus bars, etc) onto...

Some use wood because it is cheap and convenient. Some use metal, such as aluminum plate, because it is non-combustible, and grounded. While others use something non-combustible and non-conductive, like cement board (Hardiplank), Tufnol, or Bakelite.

I tried googling whether ABYC covers this and struck out, probably because I did not know the right search terms.

So, is there consensus in the boating world on this topic? Can anyone point me to something official?

Thanks!

[Lake-Effect]

Originally Posted by cw8

I'm coming from the van/RV world and, in that community, there seem to be a lot of different approaches and opinions on what to mount electrical equipment (inverters, chargers, MPPT, bus bars, etc) onto...

So, is there consensus in the boating world on this topic?

I believe the ABYC just mentions mounting such stuff securely, and to follow manufacturer's recommendations for location, ventilation, protection, access. And of course proper fusing.

I see a lot of stuff screwed to wood bulkheads or partitions without issues. If a piece of marine gear needs grounding, they put a grounding terminal on it and call it out in their installation instructions.

[Frankly]

Originally Posted by cw8

So, is there consensus in the boating world on this topic?

Not with this crowd.

For 12 Volts I use wood for mounting terminal strips, homemade Starboard, and G10 for direct contact connections usually fastened to wood. For 120 VAC I am a little more careful and only use manufactured insulated terminal connections usually mounted on wood. Also try to provide a mechanical barrier on 120 V if practical.


Frankly

[SVTatia]

Originally Posted by cw8

...Some use metal, such as aluminum plate, because it is non-combustible, and grounded...

Never on a boat.

Originally Posted by Lake-Effect

I believe the ABYC just mentions mounting such stuff securely, and to follow manufacturer's recommendations for location, ventilation, protection, access. And of course proper fusing.

I see a lot of stuff screwed to wood bulkheads or partitions without issues. If a piece of marine gear needs grounding, they put a grounding terminal on it and call it out in their installation instructions.

This^^^.

I also use phenolic when I need it, and in fact I just made a bus bar for my anchor windlass as shown below.

[cw8]

Originally Posted by SVTatia

Never on a boat.

Why not? If the component cases are all grounded (I'm not saying they are, just hypothetical), why would the surface they are mounted to being grounded be a problem? What is the danger?

Thanks!

[jamhass]

Aluminum for electrical connections is NOT a good idea. It oxidizes readily, especially in a marine environment. Moreover, the oxide is an Insulator. In (older, 70's) home wiring, a special anti-corrosion paste is essential, but less effective in a salt-rich environment.

[cw8]

Originally Posted by jamhass

Aluminum for electrical connections is NOT a good idea. It oxidizes readily, especially in a marine environment. Moreover, the oxide is an Insulator. In (older, 70's) home wiring, a special anti-corrosion paste is essential, but less effective in a salt-rich environment.

This is not about using aluminum as a 'connection'. I'm not talking about, for example, using this panel _as_ the ground for these components (any components that require a ground will be properly and correctly grounded by cable). I'm simply talking about mounting on the aluminum, which is conductive and grounded.

@SVTatie seemed to be objecting to aluminum _because_ it is grounded. I am trying to understand the reasoning/logic behind that objection.

[s/v Jedi]

The material for this is called GPO-3. It is a red colored fiberglass specially formulated for use in electrical applications.

Here I use it for the top lid of my lithium battery

[BillKny]

It depends... (It ALWAYS depends!)

There is no good reason to install a metal plate specifically to attach electrical components to. If a component requires grounding, it would be better practice to ground the case using a purpose made ground wire (which, of course you would need to attached to the metal plate anyway, so whats the benefit?) Grounding the case through the mounting hardware is not 100% reliable because the case is usually painted.

On a metal boat I would not want my grounding system connected to the hull to avoid corrosion causing current leaks, so I would deliberately isolate the case ground from the hull, using whatever material made sense. Wood in a dry place, g10, or fiberglass in damp environments.

As for bus bars and such, I have never seen one (other then some homemade kludges) that allowed any contact between the mounting hardware and the circuits being distributed. I certainly wouldn't buy or install one that did. In which case, the material of construction of the mounting plate is irrelevant, assuming it was suitable mechanically.

[Lake-Effect]

Originally Posted by cw8

This is not about using aluminum as a 'connection'. I'm not talking about, for example, using this panel _as_ the ground for these components (any components that require a ground will be properly and correctly grounded by cable). I'm simply talking about mounting on the aluminum, which is conductive and grounded.

@SVTatie seemed to be objecting to aluminum _because_ it is grounded. I am trying to understand the reasoning/logic behind that objection.

Well, the point is... why the aluminum backing? The equipment doesn't require it, it's extra expense and effort, and it's a big surface that a loose wire, or sloppy tool handling could short against. Seems like extra hassle with no benefits.

[Spot]

@ Jedi - nice looking panel!

Given a choice I'd take fiberglass over wood or phenolic in a humid environment.

[goboatingnow]

GPO-3 is also commonly designated UPGM203

[cw8]

Originally Posted by Lake-Effect

Well, the point is... why the aluminum backing? The equipment doesn't require it, it's extra expense and effort, and it's a big surface that a loose wire, or sloppy tool handling could short against. Seems like extra hassle with no benefits.

Fair question.
* You need to to use something, whether wood, metal, or plastic/etc.
* A number of folks are using old metal signs, so free or cheap.
* Aluminum, particularly if bolted to the frame of the van, would help disperse heat.
* The loose wire theory is interesting, and gets to the heart of my query. One school of thought is that you want that loose wire to contact ground, and blow a fuse. Fail hard and fast. As opposed to floating around longer and potentially touching something more dangerous and/or expensive. THIS is the question I am interested in hearing more opinions/facts/advise on. Is mounting to a grounded panel good, bad, or indifferent?

Thanks!

[Lake-Effect]

Originally Posted by cw8

Fair question.
* You need to to use something, whether wood, metal, or plastic/etc.
* A number of folks are using old metal signs, so free or cheap.
* Aluminum, particularly if bolted to the frame of the van, would help disperse heat.
* The loose wire theory is interesting, and gets to the heart of my query. One school of thought is that you want that loose wire to contact ground, and blow a fuse. Fail hard and fast. As opposed to floating around longer and potentially touching something more dangerous and/or expensive. THIS is the question I am interested in hearing more opinions/facts/advise on. Is mounting to a grounded panel good, bad, or indifferent?

Thanks!

If a person knows what they are doing, it's indifferent. If they don't, there's a number of problems that can occur if grounding is done improperly.

No marine electrical device that I know of requires external heat-sinking, just decent ventilation.

The majority of DC electrical devices have protected (covered) +12v inputs, and any metal cases are already grounded, so there's no real added protection from mounting to a metal plate.

On an RV with its metal chassis and weight sensitivity, a metal plate is light and inexpensive. Watch out for wierd corrosion with dissimilar materials (eg aluminum bolted to steel).

On a boat... (usually fiberglass)... no point to it, really.

[SVTatia]

Originally Posted by cw8

Why not? If the component cases are all grounded (I'm not saying they are, just hypothetical), why would the surface they are mounted to being grounded be a problem? What is the danger?

Thanks!

I assume you have the answers about the dangres/best practises above.
Just to close it, my issue was not with the aluminum, electrical panels are usually made of it, it is the way ground is made.
Maybe they exist, but I have not seen any marine electric/electronic component that has the case grounded, they all have the connection points (they are all plastic anyway).