. So no room left in the inside breaker panel with it full of tandems and quads already. Thinking number #1 is a panel mounted surge suppression at the outside meter/mains shut-off to the 3 buildings.
@budgetav
A whole house SPD (Surge Protective Device) is your first line of defense against high voltage transients damage. To protect your home you need a Type 2 SPD installed at the electrical panel in your triple wide MH.
FYI, read the warranty for the type 2 SPD you are looking at buying. You will find it requires the SPD be installed by a Licensed Electrician. You will want to hire an electrician to check out the grounding for the panel in the triple wide MH to make sure it meets Code.
The panel in the triple wide MH is a sub panel that is fed from the main electrical service on the pole. By Code the sub panel in the MH should be feed with 4 wires.
Two Hot ungrounded conductors, (240Vac Hot to Hot).
One Grounded Neutral Conductor. (Connected to Earth at the pole. Hopefully to two minimum 5/8" X 8ft ground rods, hopefully.)
One Equipment Grounding Conductor. (There should be a separate ground bar for all the safety equipment grounding wires to connect to. No white neutral conductors connected to the equipment ground bar.
The neutral bar should be insulated from the metal enclosure of the panel. All white insulated conductors, wires, connect to the neutral bar.
Because of your situation where the main electrical service is located outside, detached, from the MH structure I would recommend you have an Electrician install an Auxiliary Grounding Electrode (NEC 250.54) , at least two 5/8" X 8ft ground rods connected together and a bare #4 solid copper wire extended to the equipment ground bar in the electrical panel. (NEC electrical code only requires a #6 awg copper ground wire. I would recommend a #4 awg copper wire. Per NEC code the two rods must be a bare minimum of 6ft apart from one another. That is too close. Have the electrician drive them at least 8ft apart. 10ft or 12ft is better yet.
FYI, 2020 NEC 250.32 (A) requires the Earth Grounding Electrode connection. Not sure when, year, your electrical service was installed. If not required back then it is Grandfathered in. Have it installed anyway... Money well spent.
Why is the Mother Earth connection Electrode important, needed. Mainly for lightning protection. in the event of a nearby lightning strike in the event the high voltage lightning transient enters on the electrical panel you want the high voltage lightning transient diverted to mother earth quickly in the shortest lowest resistive path as possible. (Grounds rods should be driven outdoors from where the panel is located in the MH. I would recommend at least 3ft out from the MH skirting. Better chance of rain moisture in the earth to ground rod. Better conductivity.)
When you can afford it, I would recommend you install another Type 2 SPD at the main electrical service panel at the pole. The service neutral conductor is connected to mother earth there. Again you want the high voltage lightning transient diverted to mother Earth as quickly as possible.
Internet Provider.
Wire or Fiber? If wire make sure the outdoors Grounding Block is connected to the Grounding Electrode System for the MH. This is a must. How far is the grounding block from where the ground rods will be driven in the earth?
As for two breaker spaces, (2 pole breaker), in the MH electrical panel. The electrician will know how to address that.
IMO, all of the above should be done. A Type 3 point of use Surge protector will protect better. Hopefully any high voltage transient surges will be taken care of before it reaches the Type 3 point of use protector.
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